--- loncom/homework/grades.pm	2009/08/19 19:25:21	1.579
+++ loncom/homework/grades.pm	2010/01/15 16:41:43	1.588
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # The LON-CAPA Grading handler
 #
-# $Id: grades.pm,v 1.579 2009/08/19 19:25:21 raeburn Exp $
+# $Id: grades.pm,v 1.588 2010/01/15 16:41:43 bisitz Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -97,9 +97,15 @@ sub ssi_print_error {
 #
 # --- Retrieve the parts from the metadata file.---
 sub getpartlist {
-    my ($symb) = @_;
+    my ($symb,$errorref) = @_;
 
     my $navmap   = Apache::lonnavmaps::navmap->new();
+    unless (ref($navmap)) {
+        if (ref($errorref)) { 
+            $$errorref = 'navmap';
+            return;
+        }
+    }
     my $res      = $navmap->getBySymb($symb);
     my $partlist = $res->parts();
     my $url      = $res->src();
@@ -144,9 +150,15 @@ sub nameUserString {
 #--- Get the partlist and the response type for a given problem. ---
 #--- Indicate if a response type is coded handgraded or not. ---
 sub response_type {
-    my ($symb) = shift;
+    my ($symb,$response_error) = @_;
 
     my $navmap = Apache::lonnavmaps::navmap->new();
+    unless (ref($navmap)) {
+        if (ref($response_error)) {
+            $$response_error = 1;
+        }
+        return;
+    }
     my $res = $navmap->getBySymb($symb);
     my $partlist = $res->parts();
     my %vPart = 
@@ -194,37 +206,49 @@ sub get_display_part {
 #--- Show resource title
 #--- and parts and response type
 sub showResourceInfo {
-    my ($symb,$probTitle,$checkboxes) = @_;
-    my $col=3;
-    if ($checkboxes) { $col=4; }
+    my ($symb,$probTitle,$checkboxes,$res_error) = @_;
     my $result = '<h3>'.&mt('Current Resource').': '.$probTitle.'</h3>'."\n";
-    $result .='<table border="0">';
-    my ($partlist,$handgrade,$responseType) = &response_type($symb);
+    my ($partlist,$handgrade,$responseType) = &response_type($symb,$res_error);
+    if (ref($res_error)) {
+        if ($$res_error) {
+            return;
+        }
+    }
+    $result.=&Apache::loncommon::start_data_table()
+            .&Apache::loncommon::start_data_table_header_row();
+    if ($checkboxes) {
+        $result.='<th>&nbsp;</th>';
+    }
+    $result.='<th>'.&mt('Problem Part').'</th>'
+            .'<th>'.&mt('Res. ID').'</th>'
+            .'<th>'.&mt('Type').'</th>'
+            .&Apache::loncommon::end_data_table_header_row();
     my %resptype = ();
     my $hdgrade='no';
     my %partsseen;
     foreach my $partID (sort(keys(%$responseType))) {
-	foreach my $resID (sort(keys(%{ $responseType->{$partID} }))) {
-	    my $handgrade=$$handgrade{$partID.'_'.$resID};
-	    my $responsetype = $responseType->{$partID}->{$resID};
-	    $hdgrade = $handgrade if ($handgrade eq 'yes');
-	    $result.='<tr>';
-	    if ($checkboxes) {
-		if (exists($partsseen{$partID})) {
-		    $result.="<td>&nbsp;</td>";
-		} else {
-		    $result.="<td><input type='checkbox' name='vPart' value='$partID' checked='checked' /></td>";
-		}
-		$partsseen{$partID}=1;
-	    }
-	    my $display_part=&get_display_part($partID,$symb);
-            $result.='<td><b>'.&mt('Part: [_1]',$display_part).'</b>'.
-                ' <span class="LC_internal_info">'.$resID.'</span></td>'.
-                '<td><b>'.&mt('Type: [_1]',$responsetype).'</b></td></tr>';
-#	    '<td>'.&mt('<b>Handgrade: </b>[_1]',$handgrade).'</td></tr>';
-	}
+        foreach my $resID (sort(keys(%{ $responseType->{$partID} }))) {
+            my $handgrade=$$handgrade{$partID.'_'.$resID};
+            my $responsetype = $responseType->{$partID}->{$resID};
+            $hdgrade = $handgrade if ($handgrade eq 'yes');
+            $result.=&Apache::loncommon::start_data_table_row();
+            if ($checkboxes) {
+                if (exists($partsseen{$partID})) {
+                    $result.="<td>&nbsp;</td>";
+                } else {
+                    $result.="<td><input type='checkbox' name='vPart' value='$partID' checked='checked' /></td>";
+                }
+                $partsseen{$partID}=1;
+            }
+            my $display_part=&get_display_part($partID,$symb);
+            $result.='<td>'.$display_part.'</td>'
+                    .'<td>'.'<span class="LC_internal_info">'.$resID.'</span></td>'
+                    .'<td>'.&mt($responsetype).'</td>'
+#                   .'<td>'.&mt('<b>Handgrade: </b>[_1]',$handgrade).'</td>'
+                    .&Apache::loncommon::end_data_table_row();
+        }
     }
-    $result.='</table>'."\n";
+    $result.=&Apache::loncommon::end_data_table();
     return $result,$responseType,$hdgrade,$partlist,$handgrade;
 }
 
@@ -755,7 +779,7 @@ sub verifyreceipt {
 
     my $title.=
 	'<h3><span class="LC_info">'.
-	&mt('Verifying  Receipt No. [_1]',$receipt).
+	&mt('Verifying Receipt No. [_1]',$receipt).
 	'</span></h3>'."\n".
 	'<h4>'.&mt('<b>Resource: </b>[_1]',$env{'form.probTitle'}).
 	'</h4>'."\n";
@@ -767,7 +791,13 @@ sub verifyreceipt {
     if ($env{"course.$courseid.receiptalg"} eq 'receipt2' ||
 	$env{"course.$courseid.receiptalg"} eq 'receipt3') { $receiptparts=1; }
     my $parts=['0'];
-    if ($receiptparts) { ($parts)=&response_type($symb); }
+    if ($receiptparts) {
+        my $res_error; 
+        ($parts)=&response_type($symb,\$res_error);
+        if ($res_error) {
+            return &navmap_errormsg();
+        } 
+    }
     
     my $header = 
 	&Apache::loncommon::start_data_table().
@@ -809,11 +839,14 @@ sub verifyreceipt {
 	}
     }
     if ($matches == 0) {
-	$string = $title.&mt('No match found for the above receipt.');
+        $string = $title
+                 .'<p class="LC_warning">'
+                 .&mt('No match found for the above receipt number.')
+                 .'</p>';
     } else {
 	$string = &jscriptNform($symb).$title.
 	    '<p>'.
-	    &mt('The above receipt matches the following [numerate,_1,student].',$matches).
+	    &mt('The above receipt number matches the following [quant,_1,student].',$matches).
 	    '</p>'.
 	    $header.
 	    $contents.
@@ -1678,6 +1711,25 @@ sub get_increment {
     return $increment;
 }
 
+sub gradeBox_start {
+    return (
+        &Apache::loncommon::start_data_table()
+       .&Apache::loncommon::start_data_table_header_row()
+       .'<th>'.&mt('Part').'</th>'
+       .'<th>'.&mt('Points').'</th>'
+       .'<th>&nbsp;</th>'
+       .'<th>'.&mt('Assign Grade').'</th>'
+       .'<th>'.&mt('Weight').'</th>'
+       .'<th>'.&mt('Grade Status').'</th>'
+       .&Apache::loncommon::end_data_table_header_row()
+    );
+}
+
+sub gradeBox_end {
+    return (
+        &Apache::loncommon::end_data_table()
+    );
+}
 #--- displays the grading box, used in essay type problem and grading by page/sequence
 sub gradeBox {
     my ($request,$symb,$uname,$udom,$counter,$partid,$record) = @_;
@@ -1697,7 +1749,7 @@ sub gradeBox {
     if ($last_resets{$partid}) {
         $aggtries = &get_num_tries($record,$last_resets{$partid},$partid);
     }
-    $result.='<table border="0"><tr>';
+    $result.=&Apache::loncommon::start_data_table_row();
     my $ctr = 0;
     my $thisweight = 0;
     my $increment = &get_increment();
@@ -1720,8 +1772,8 @@ sub gradeBox {
 	$wgt.')" /></td>'."\n";
     $line.='<td>/'.$wgt.' '.$wgtmsg.
 	($$record{'resource.'.$partid.'.solved'} eq 'correct_by_student' ? '&nbsp;'.$checkIcon : '').
-	' </td><td><b>'.&mt('Grade Status').':</b>'."\n";
-    $line.='<select name="GD_SEL'.$counter.'_'.$partid.'" '.
+	' </td>'."\n";
+    $line.='<td><select name="GD_SEL'.$counter.'_'.$partid.'" '.
 	'onChange="javascript:clearRadBox(this.form,\''.$counter.'_'.$partid.'\')" >'."\n";
     if ($$record{'resource.'.$partid.'.solved'} eq 'excused') {
 	$line.='<option></option>'.
@@ -1735,9 +1787,8 @@ sub gradeBox {
 
 	#&mt('<td><b>Part:</b></td><td>[_1]</td><td><b>Points:</b></td><td>[_2]</td><td>or</td><td>[_3]</td>',$display_part,$radio,$line);
     $result .= 
-	    '<td><b>'.&mt('Part:').'</b></td><td>'.$display_part.'</td><td><b>'.&mt('Points:').'</b></td><td>'.$radio.'</td><td>'.&mt('or').'</td><td>'.$line.'</td>'.
-    
-    $result.='</tr></table>'."\n";
+	    '<td>'.$display_part.'</td><td>'.$radio.'</td><td>'.&mt('or').'</td><td>'.$line.'</td>';
+    $result.=&Apache::loncommon::end_data_table_row();
     $result.='<input type="hidden" name="stores'.$counter.'_'.$partid.'" value="" />'."\n".
 	'<input type="hidden" name="oldpts'.$counter.'_'.$partid.'" value="'.$score.'" />'."\n".
 	'<input type="hidden" name="solved'.$counter.'_'.$partid.'" value="'.
@@ -1746,13 +1797,17 @@ sub gradeBox {
         $$record{'resource.'.$partid.'.tries'}.'" />'."\n".
         '<input type="hidden" name="aggtries'.$counter.'_'.$partid.'" value="'.
         $aggtries.'" />'."\n";
-    $result.=&handback_box($symb,$uname,$udom,$counter,$partid,$record);
+    my $res_error;
+    $result.=&handback_box($symb,$uname,$udom,$counter,$partid,$record,\$res_error);
+    if ($res_error) {
+        return &navmap_errormsg();
+    }
     return $result;
 }
 
 sub handback_box {
-    my ($symb,$uname,$udom,$counter,$partid,$record) = @_;
-    my ($partlist,$handgrade,$responseType) = &response_type($symb);
+    my ($symb,$uname,$udom,$counter,$partid,$record,$res_error) = @_;
+    my ($partlist,$handgrade,$responseType) = &response_type($symb,$res_error);
     my (@respids);
      my @part_response_id = &flatten_responseType($responseType);
     foreach my $part_response_id (@part_response_id) {
@@ -1814,26 +1869,23 @@ sub show_problem {
 	$companswer=~s|name="submit"|name="would_have_been_submit"|g;
     }
     $rendered=
-	'<div class="LC_grade_show_problem_header">'.
-	&mt('View of the problem').
-	'</div><div class="LC_grade_show_problem_problem">'.
-	$rendered.
-	'</div>';
+        '<div class="LC_Box">'
+       .'<h3 class="LC_hcell">'.&mt('View of the problem').'</h3>'
+       .$rendered
+       .'</div>';
     $companswer=
-	'<div class="LC_grade_show_problem_header">'.
-	&mt('Correct answer').
-	'</div><div class="LC_grade_show_problem_problem">'.
-	$companswer.
-	'</div>';
+        '<div class="LC_Box">'
+       .'<h3 class="LC_hcell">'.&mt('Correct answer').'</h3>'
+       .$companswer
+       .'</div>';
     my $result;
     if ($mode eq 'both') {
-	$result=$rendered.$companswer;
+        $result=$rendered.$companswer;
     } elsif ($mode eq 'text') {
-	$result=$rendered;
+        $result=$rendered;
     } elsif ($mode eq 'answer') {
-	$result=$companswer;
+        $result=$companswer;
     }
-    $result='<div class="LC_grade_show_problem">'.$result.'</div>';
     return $result;
 }
 
@@ -2047,24 +2099,27 @@ KEYWORDS
     }
 
     my %record = &Apache::lonnet::restore($symb,$env{'request.course.id'},$udom,$uname);
-    my ($partlist,$handgrade,$responseType) = &response_type($symb);
+    my $res_error;
+    my ($partlist,$handgrade,$responseType) = &response_type($symb,\$res_error);
+    if ($res_error) {
+        $request->print(&navmap_errormsg());
+        return;
+    }
 
     # Display student info
     $request->print(($counter == 0 ? '' : '<br />'));
     my $result='<div class="LC_grade_submissions">';
     
-    $result.='<div class="LC_grade_submissions_header">';
-    $result.= &mt('Submissions');
+    $result.='<div class="LC_Box">'
+            .'<h3 class="LC_hcell">'.&mt('Submissions').'</h3>';
     $result.='<input type="hidden" name="name'.$counter.
-	'" value="'.$env{'form.fullname'}.'" />'."\n";
+             '" value="'.$env{'form.fullname'}.'" />'."\n";
     if ($env{'form.handgrade'} eq 'no') {
-	$result.='<span class="LC_grade_check_note">'.
-	    &mt('Part(s) graded correct by the computer is marked with a [_1] symbol.',$checkIcon)."</span>\n";
-
+        $result.='<p class="LC_info">'
+                .&mt('Part(s) graded correct by the computer is marked with a [_1] symbol.',$checkIcon)
+                ."</p>\n";
     }
 
-
-
     # If any part of the problem is an essay-response (handgraded), then check for collaborators
     my $fullname;
     my $col_fullnames = [];
@@ -2075,9 +2130,9 @@ KEYWORDS
 	$result.=$sub_result;
     }
     $request->print($result."\n");
-    $request->print('</div>'."\n");
+
     # print student answer/submission
-    # Options are (1) Handgaded submission only
+    # Options are (1) Handgraded submission only
     #             (2) Last submission, includes submission that is not handgraded 
     #                  (for multi-response type part)
     #             (3) Last submission plus the parts info
@@ -2087,10 +2142,10 @@ KEYWORDS
 	
 	my $lastsubonly;
 
-	if ($$timestamp eq '') {
-	    $lastsubonly.='<div class="LC_grade_submissions_body">'.$$string[0].'</div>'; 
-	} else {
-	    $lastsubonly = '<div class="LC_grade_submissions_body"> <b>Date Submitted:</b> '.$$timestamp."\n";
+        if ($$timestamp eq '') {
+            $lastsubonly.='<div class="LC_grade_submissions_body">'.$$string[0].'</div>'; 
+        } else {
+            $lastsubonly = '<div class="LC_grade_submissions_body"> <b>Date Submitted:</b> '.$$timestamp."\n";
 
 	    my %seenparts;
 	    my @part_response_id = &flatten_responseType($responseType);
@@ -2178,7 +2233,7 @@ KEYWORDS
 		    }
 		}
 	    }
-	    $lastsubonly.='</div>'."\n";
+	    $lastsubonly.='</div>'."\n"; # End: LC_grade_submissions_body
 	}
 	$request->print($lastsubonly);
    } elsif ($env{'form.lastSub'} eq 'datesub') {
@@ -2240,11 +2295,11 @@ KEYWORDS
     my @partlist;
     my @gradePartRespid;
     my @part_response_id = &flatten_responseType($responseType);
-    $request->print('<div class="LC_grade_assign">'.
-		    
-		    '<div class="LC_grade_assign_header">'.
-		    &mt('Assign Grades').'</div>'.
-		    '<div class="LC_grade_assign_body">');
+    $request->print(
+        '<div class="LC_Box">'
+       .'<h3 class="LC_hcell">'.&mt('Assign Grades').'</h3>'
+    );
+    $request->print(&gradeBox_start()); # <div class="LC_grade_assign_body">
     foreach my $part_response_id (@part_response_id) {
     	my ($partid,$respid) = @{ $part_response_id };
 	my $part_resp = join('_',@{ $part_response_id });
@@ -2256,7 +2311,8 @@ KEYWORDS
 	push(@gradePartRespid,$partid.'.'.$respid);
 	$request->print(&gradeBox($request,$symb,$uname,$udom,$counter,$partid,\%record));
     }
-    $request->print('</div></div>');
+    $request->print(&gradeBox_end()); # </div>
+    $request->print('</div>');
 
     $request->print('<div class="LC_grade_info_links">');
     if ($perm{'vgr'}) {
@@ -2598,7 +2654,12 @@ sub processHandGrade {
     }
     $ctr = 0;
     @parsedlist = reverse @parsedlist if ($button eq 'Previous');
-    my ($partlist) = &response_type($symb);
+    my $res_error;
+    my ($partlist) = &response_type($symb,\$res_error);
+    if ($res_error) {
+        $request->print(&navmap_errormsg());
+        return;
+    }
     foreach my $student (@parsedlist) {
 	my $submitonly=$env{'form.submitonly'};
 	my ($uname,$udom) = split(/:/,$student);
@@ -2796,8 +2857,12 @@ sub check_and_remove_from_queue {
 sub handback_files {
     my ($request,$symb,$stuname,$domain,$newflg,$new_part,$newrecord) = @_;
     my $portfolio_root = '/userfiles/portfolio';
-    my ($partlist,$handgrade,$responseType) = &response_type($symb);
-
+    my $res_error;
+    my ($partlist,$handgrade,$responseType) = &response_type($symb,\$res_error);
+    if ($res_error) {
+        $request->print('<br />'.&navmap_errormsg().'<br />');
+        return;
+    }
     my @part_response_id = &flatten_responseType($responseType);
     foreach my $part_response_id (@part_response_id) {
     	my ($part_id,$resp_id) = @{ $part_response_id };
@@ -3255,7 +3320,11 @@ sub viewgrades {
     $result.= '<h3>'.$common_header.'</h3>'.&Apache::loncommon::start_data_table();
     #radio buttons/text box for assigning points for a section or class.
     #handles different parts of a problem
-    my ($partlist,$handgrade,$responseType) = &response_type($symb);
+    my $res_error;
+    my ($partlist,$handgrade,$responseType) = &response_type($symb,\$res_error);
+    if ($res_error) {
+        return &navmap_errormsg();
+    }
     my %weight = ();
     my $ctsparts = 0;
     my %seen = ();
@@ -3315,7 +3384,11 @@ sub viewgrades {
 	      &Apache::loncommon::start_data_table_header_row().
 	      '<th>'.&mt('No.').'</th>'.
 	      '<th>'.&nameUserString('header')."</th>\n";
-    my (@parts) = sort(&getpartlist($symb));
+    my $partserror;
+    my (@parts) = sort(&getpartlist($symb,\$partserror));
+    if ($partserror) {
+        return &navmap_errormsg();
+    }
     my (undef,undef,$url)=&Apache::lonnet::decode_symb($symb);
     my @partids = ();
     foreach my $part (@parts) {
@@ -3474,7 +3547,11 @@ sub editgrades {
     my %columns = ();
     my ($i,$ctr,$count,$rec_update) = (0,0,0,0);
 
-    my (@parts) = sort(&getpartlist($symb));
+    my $partserror;
+    my (@parts) = sort(&getpartlist($symb,\$partserror));
+    if ($partserror) {
+        return &navmap_errormsg();
+    }
     my $header;
     while ($ctr < $env{'form.totalparts'}) {
 	my $partid = $env{'form.partid_'.$ctr};
@@ -3806,8 +3883,14 @@ ENDPICK
 }
 
 sub csvupload_fields {
-    my ($symb) = @_;
-    my (@parts) = &getpartlist($symb);
+    my ($symb,$errorref) = @_;
+    my (@parts) = &getpartlist($symb,$errorref);
+    if (ref($errorref)) {
+        if ($$errorref) {
+            return;
+        }
+    }
+
     my @fields=(['ID','Student/Employee ID'],
 		['username','Student Username'],
 		['domain','Student Domain']);
@@ -3907,8 +3990,12 @@ sub csvuploadmap {
     &csvuploadmap_header($request,$symb,$datatoken,$#records+1);
     my ($i,$keyfields);
     if (@records) {
-	my @fields=&csvupload_fields($symb);
-
+        my $fieldserror;
+	my @fields=&csvupload_fields($symb,\$fieldserror);
+        if ($fieldserror) {
+            $request->print(&navmap_errormsg());
+            return;
+        }
 	if ($env{'form.upfile_associate'} eq 'reverse') {	
 	    &Apache::loncommon::csv_print_samples($request,\@records);
 	    $i=&Apache::loncommon::csv_print_select_table($request,\@records,
@@ -4144,7 +4231,12 @@ LISTJAVASCRIPT
 	&mt('Manual Grading by Page or Sequence').'</span></h3>';
 
     $result.='<form action="/adm/grades" method="post" name="displayPage">'."\n";
-    my ($titles,$symbx) = &getSymbMap();
+    my $map_error;
+    my ($titles,$symbx) = &getSymbMap($map_error);
+    if ($map_error) {
+        $request->print(&navmap_errormsg());
+        return; 
+    }
     my ($curpage) =&Apache::lonnet::decode_symb($symb); 
 #    my ($curpage,$mapId) =&Apache::lonnet::decode_symb($symb); 
 #    my $type=($curpage =~ /\.(page|sequence)/);
@@ -4239,8 +4331,14 @@ LISTJAVASCRIPT
 }
 
 sub getSymbMap {
+    my ($map_error) = @_;
     my $navmap = Apache::lonnavmaps::navmap->new();
-
+    unless (ref($navmap)) {
+        if (ref($map_error)) {
+            $$map_error = 'navmap';
+        }
+        return;
+    }
     my %symbx = ();
     my @titles = ();
     my $minder = 0;
@@ -4299,6 +4397,11 @@ sub displayPage {
     $request->print($result);
 
     my $navmap = Apache::lonnavmaps::navmap->new();
+    unless (ref($navmap)) {
+        $request->print(&navmap_errormsg());
+        $request->print(&show_grading_menu_form($symb));
+        return;
+    }
     my ($mapUrl, $id, $resUrl)=&Apache::lonnet::decode_symb($env{'form.page'});
     my $map = $navmap->getResourceByUrl($resUrl); # add to navmaps
     if (!$map) {
@@ -4397,11 +4500,13 @@ sub displayPage {
  
 	    }
 	    if (&canmodify($usec)) {
+            $studentTable.=&gradeBox_start();
 		foreach my $partid (@{$parts}) {
 		    $studentTable.=&gradeBox($request,$symbx,$uname,$udom,$question,$partid,\%record);
 		    $studentTable.='<input type="hidden" name="q_'.$question.'" value="'.$partid.'" />'."\n";
 		    $question++;
 		}
+            $studentTable.=&gradeBox_end();
 		$prob++;
 	    }
 	    $studentTable.='</td></tr>';
@@ -4553,7 +4658,12 @@ sub updateGradeByPage {
 
     $request->print($result);
 
+
     my $navmap = Apache::lonnavmaps::navmap->new();
+    unless (ref($navmap)) {
+        $request->print(&navmap_errormsg());
+        return;
+    }
     my ($mapUrl, $id, $resUrl) = &Apache::lonnet::decode_symb( $env{'form.page'});
     my $map = $navmap->getResourceByUrl($resUrl); # add to navmaps
     if (!$map) {
@@ -4698,7 +4808,7 @@ sub updateGradeByPage {
 #
 #-------------------------------------------------------------------
 
-#--------------------Scantron Grading-----------------------------------
+#-------------------- Bubblesheet (Scantron) Grading -------------------
 #
 #------ start of section for handling grading by page/sequence ---------
 
@@ -4776,14 +4886,19 @@ sub defaultFormData {
    Return html dropdown of possible sequences to grade
  
  Arguments:
-   $symb - $symb of the current resource 
+   $symb - $symb of the current resource
+   $map_error - ref to scalar which will container error if
+                $navmap object is unavailable in &getSymbMap().
 
 =cut
 
 sub getSequenceDropDown {
-    my ($symb)=@_;
+    my ($symb,$map_error)=@_;
     my $result='<select name="selectpage">'."\n";
-    my ($titles,$symbx) = &getSymbMap();
+    my ($titles,$symbx) = &getSymbMap($map_error);
+    if (ref($map_error)) {
+        return if ($$map_error);
+    }
     my ($curpage)=&Apache::lonnet::decode_symb($symb); 
     my $ctr=0;
     foreach (@$titles) {
@@ -5049,7 +5164,12 @@ sub scantron_selectphase {
     my ($r,$file2grade) = @_;
     my ($symb)=&get_symb($r);
     if (!$symb) {return '';}
-    my $sequence_selector=&getSequenceDropDown($symb);
+    my $map_error;
+    my $sequence_selector=&getSequenceDropDown($symb,\$map_error);
+    if ($map_error) {
+        $r->print('<br />'.&navmap_errormsg().'<br />');
+        return;
+    }
     my $default_form_data=&defaultFormData($symb);
     my $grading_menu_button=&show_grading_menu_form($symb);
     my $file_selector=&scantron_uploads($file2grade);
@@ -6223,7 +6343,12 @@ sub scantron_validate_file {
     $r->print('<p>'.&mt('Gathering necessary information.').'</p>');$r->rflush();
     #get the student pick code ready
     $r->print(&Apache::loncommon::studentbrowser_javascript());
-    my $max_bubble=&scantron_get_maxbubble();
+    my $nav_error;
+    my $max_bubble=&scantron_get_maxbubble(\$nav_error);
+    if ($nav_error) {
+        $r->print(&navmap_errormsg());
+        return '';
+    }
     my $result=&scantron_form_start($max_bubble).$default_form_data;
     $r->print($result);
     
@@ -6635,6 +6760,10 @@ sub scantron_validate_sequence {
     my ($r,$currentphase) = @_;
 
     my $navmap=Apache::lonnavmaps::navmap->new();
+    unless (ref($navmap)) {
+        $r->print(&navmap_errormsg());
+        return (1,$currentphase);
+    }
     my (undef,undef,$sequence)=
 	&Apache::lonnet::decode_symb($env{'form.selectpage'});
 
@@ -6666,8 +6795,13 @@ sub scantron_validate_ID {
     #get scantron line setup
     my %scantron_config=&get_scantron_config($env{'form.scantron_format'});
     my ($scanlines,$scan_data)=&scantron_getfile();
-    
-    &scantron_get_maxbubble();	# parse needs the bubble_lines.. array.
+
+    my $nav_error;
+    &scantron_get_maxbubble(\$nav_error); # parse needs the bubble_lines.. array.
+    if ($nav_error) {
+        $r->print(&navmap_errormsg());
+        return(1,$currentphase);
+    }
 
     my %found=('ids'=>{},'usernames'=>{});
     for (my $i=0;$i<=$scanlines->{'count'};$i++) {
@@ -7220,7 +7354,12 @@ sub scantron_validate_CODE {
 
     my %allcodes=&get_codes();
 
-    &scantron_get_maxbubble();	# parse needs the lines per response array.
+    my $nav_error;
+    &scantron_get_maxbubble(\$nav_error); # parse needs the lines per response array.
+    if ($nav_error) {
+        $r->print(&navmap_errormsg());
+        return(1,$currentphase);
+    }
 
     my ($scanlines,$scan_data)=&scantron_getfile();
     for (my $i=0;$i<=$scanlines->{'count'};$i++) {
@@ -7274,7 +7413,12 @@ sub scantron_validate_doublebubble {
     #get scantron line setup
     my %scantron_config=&get_scantron_config($env{'form.scantron_format'});
     my ($scanlines,$scan_data)=&scantron_getfile();
-    &scantron_get_maxbubble();	# parse needs the bubble line array.
+    my $nav_error;
+    &scantron_get_maxbubble(\$nav_error); # parse needs the bubble line array.
+    if ($nav_error) {
+        $r->print(&navmap_errormsg());
+        return(1,$currentphase);
+    }
 
     for (my $i=0;$i<=$scanlines->{'count'};$i++) {
 	my $line=&scantron_get_line($scanlines,$scan_data,$i);
@@ -7292,6 +7436,7 @@ sub scantron_validate_doublebubble {
 
 
 sub scantron_get_maxbubble {
+    my ($nav_error) = @_;
     if (defined($env{'form.scantron_maxbubble'}) &&
 	$env{'form.scantron_maxbubble'}) {
 	&restore_bubble_lines();
@@ -7302,6 +7447,11 @@ sub scantron_get_maxbubble {
 	&Apache::lonnet::decode_symb($env{'form.selectpage'});
 
     my $navmap=Apache::lonnavmaps::navmap->new();
+    unless (ref($navmap)) {
+        if (ref($nav_error)) {
+            $$nav_error = 1;
+        }
+    }
     my $map=$navmap->getResourceByUrl($sequence);
     my @resources=$navmap->retrieveResources($map,\&scantron_filter,1,0);
 
@@ -7391,7 +7541,11 @@ sub scantron_validate_missingbubbles {
     #get scantron line setup
     my %scantron_config=&get_scantron_config($env{'form.scantron_format'});
     my ($scanlines,$scan_data)=&scantron_getfile();
-    my $max_bubble=&scantron_get_maxbubble();
+    my $nav_error;
+    my $max_bubble=&scantron_get_maxbubble(\$nav_error);
+    if ($nav_error) {
+        return(1,$currentphase);
+    }
     if (!$max_bubble) { $max_bubble=2**31; }
     for (my $i=0;$i<=$scanlines->{'count'};$i++) {
 	my $line=&scantron_get_line($scanlines,$scan_data,$i);
@@ -7451,13 +7605,24 @@ sub scantron_process_students {
     my $classlist=&Apache::loncoursedata::get_classlist();
     my %idmap=&username_to_idmap($classlist);
     my $navmap=Apache::lonnavmaps::navmap->new();
+    unless (ref($navmap)) {
+        $r->print(&navmap_errormsg());
+        return '';
+    }  
     my $map=$navmap->getResourceByUrl($sequence);
     my @resources=$navmap->retrieveResources($map,\&scantron_filter,1,0);
     my (%grader_partids_by_symb,%grader_randomlists_by_symb);
     &graders_resources_pass(\@resources,\%grader_partids_by_symb,
                             \%grader_randomlists_by_symb);
+    my $resource_error;
     foreach my $resource (@resources) {
-        my $ressymb = $resource->symb();
+        my $ressymb;
+        if (ref($resource)) {
+            $ressymb = $resource->symb();
+        } else {
+            $resource_error = 1;
+            last;
+        }
         my ($analysis,$parts) =
             &scantron_partids_tograde($resource,$env{'request.course.id'},
                                       $env{'user.name'},$env{'user.domain'},1);
@@ -7469,6 +7634,10 @@ sub scantron_process_students {
             }
         }
     }
+    if ($resource_error) {
+        $r->print(&navmap_errormsg());
+        return '';
+    }
 
     my ($uname,$udom);
     my $result= <<SCANTRONFORM;
@@ -7493,7 +7662,12 @@ SCANTRONFORM
     my $i=-1;
     my $started;
 
-    &scantron_get_maxbubble();	# Need the bubble lines array to parse.
+    my $nav_error;
+    &scantron_get_maxbubble(\$nav_error); # Need the bubble lines array to parse.
+    if ($nav_error) {
+        $r->print(&navmap_errormsg());
+        return '';
+    }
 
     # If an ssi failed in scantron_get_maxbubble, put an error message out to
     # the user and return.
@@ -7534,9 +7708,15 @@ SCANTRONFORM
  	}
   	($uname,$udom)=split(/:/,$uname);
 
-        my %partids_by_symb;
+        my (%partids_by_symb,$res_error);
         foreach my $resource (@resources) {
-            my $ressymb = $resource->symb();
+            my $ressymb;
+            if (ref($resource)) {
+                $ressymb = $resource->symb();
+            } else {
+                $res_error = 1;
+                last;
+            }
             if ((exists($grader_randomlists_by_symb{$ressymb})) ||
                 (ref($grader_partids_by_symb{$ressymb}) ne 'ARRAY')) {
                 my ($analysis,$parts) =
@@ -7547,6 +7727,12 @@ SCANTRONFORM
             }
         }
 
+        if ($res_error) {
+            &scantron_add_delay(\@delayqueue,$line,
+                                'An error occurred while grading student '.$uname,2);
+            next;
+        }
+
 	&Apache::lonxml::clear_problem_counter();
   	&Apache::lonnet::appenv($scan_record);
 
@@ -7977,6 +8163,10 @@ sub checkscantron_results {
     my $classlist=&Apache::loncoursedata::get_classlist();
     my %idmap=&Apache::grades::username_to_idmap($classlist);
     my $navmap=Apache::lonnavmaps::navmap->new();
+    unless (ref($navmap)) {
+        $r->print(&navmap_errormsg());
+        return '';
+    }
     my $map=$navmap->getResourceByUrl($sequence);
     my @resources=$navmap->retrieveResources($map,\&scantron_filter,1,0);
     my (%grader_partids_by_symb,%grader_randomlists_by_symb);
@@ -7991,12 +8181,16 @@ sub checkscantron_results {
     my %completedstudents;
 
     my $count=&Apache::grades::get_todo_count($scanlines,$scan_data);
-    my %prog_state=&Apache::lonhtmlcommon::Create_PrgWin($r,'Scantron/Submissions Comparison Status',
-                                    'Progress of Scantron Data/Submission Records Comparison',$count,
+    my %prog_state=&Apache::lonhtmlcommon::Create_PrgWin($r,'Bubblesheet/Submissions Comparison Status',
+                                    'Progress of Bubblesheet Data/Submission Records Comparison',$count,
                                     'inline',undef,'checkscantron');
     my ($username,$domain,$started);
-
-    &scantron_get_maxbubble();  # Need the bubble lines array to parse.
+    my $nav_error;
+    &scantron_get_maxbubble(\$nav_error); # Need the bubble lines array to parse.
+    if ($nav_error) {
+        $r->print(&navmap_errormsg());
+        return '';
+    }
 
     &Apache::lonhtmlcommon::Update_PrgWin($r,\%prog_state,
                                           'Processing first student');
@@ -8069,14 +8263,14 @@ sub checkscantron_results {
                 if ($scandata{$pid} eq $record{$pid}) {
                     my $css_class = ($passed % 2)?'LC_odd_row':'LC_even_row';
                     $okstudents .= '<tr class="'.$css_class.'">'.
-'<td>'.&mt('Scantron').'</td><td>'.$showscandata.'</td><td rowspan="2">'.$last.'</td><td rowspan="2">'.$pid.'</td>'."\n".
+'<td>'.&mt('Bubblesheet').'</td><td>'.$showscandata.'</td><td rowspan="2">'.$last.'</td><td rowspan="2">'.$pid.'</td>'."\n".
 '</tr>'."\n".
 '<tr class="'.$css_class.'">'."\n".
 '<td>Submissions</td><td>'.$showrecord.'</td></tr>'."\n";
                     $passed ++;
                 } else {
                     my $css_class = ($failed % 2)?'LC_odd_row':'LC_even_row';
-                    $badstudents .= '<tr class="'.$css_class.'"><td>'.&mt('Scantron').'</td><td><span class="LC_nobreak">'.$scandata{$pid}.'</span></td><td rowspan="2">'.$last.'</td><td rowspan="2">'.$pid.'</td>'."\n".
+                    $badstudents .= '<tr class="'.$css_class.'"><td>'.&mt('Bubblesheet').'</td><td><span class="LC_nobreak">'.$scandata{$pid}.'</span></td><td rowspan="2">'.$last.'</td><td rowspan="2">'.$pid.'</td>'."\n".
 '</tr>'."\n".
 '<tr class="'.$css_class.'">'."\n".
 '<td>Submissions</td><td><span class="LC_nobreak">'.$record{$pid}.'</span></td>'."\n".
@@ -8321,7 +8515,7 @@ sub grading_menu {
                     		icon => 'addClickerInfoFile.png',
                     		linktitle => 'Specify a file containing the clicker information for this resource.'
                 	    },
-                	    {	linktext => 'Grade/Manage/Review Scantron Forms',
+                	    {	linktext => 'Grade/Manage/Review Bubblesheets',
                     		url => $url4,
                     		permission => 'F',
                     		icon => 'stat.png',
@@ -8347,7 +8541,7 @@ sub grading_menu {
 
     $Str .= Apache::lonhtmlcommon::generate_menu(@menu);
     #$menudata->{'jscript'}
-    $Str .='<hr /><input type="button" value="'.&mt('Verify Receipt').'" '.
+    $Str .='<hr /><input type="button" value="'.&mt('Verify Receipt No.').'" '.
         ' onClick="javascript:checkChoice(document.forms.gradingMenu,\'5\',\'verify\')" '.
         ' /> '.
         &Apache::lonnet::recprefix($env{'request.course.id'}).
@@ -8990,7 +9184,11 @@ sub assign_clicker_grades {
     my ($symb)=&get_symb($r);
     if (!$symb) {return '';}
 # See which part we are saving to
-    my ($partlist,$handgrade,$responseType) = &response_type($symb);
+    my $res_error;
+    my ($partlist,$handgrade,$responseType) = &response_type($symb,\$res_error);
+    if ($res_error) {
+        return &navmap_errormsg();
+    }
 # FIXME: This should probably look for the first handgradeable part
     my $part=$$partlist[0];
 # Start screen output
@@ -9094,6 +9292,13 @@ ENDHEADER
     return $result.&show_grading_menu_form($symb);
 }
 
+sub navmap_errormsg {
+    return '<div class="LC_error">'.
+           &mt('An error occurred retrieving information about resources in the course.').'<br />'.
+           &mt('It is recommended that you [_1]re-initialize the course[_2] and then return to this grading page..','<a href="/adm/roles?selectrole=1&newrole='.$env{'request.role'}.'">','</a>').
+           '</div>';
+}
+
 sub handler {
     my $request=$_[0];
     &reset_caches();
@@ -9319,6 +9524,13 @@ ssi_with_retries()
 
 =item  scantron_get_maxbubble() : 
 
+   Arguments:
+       $nav_error  - Reference to scalar which is a flag to indicate a
+                      failure to retrieve a navmap object.
+       if $nav_error is set to 1 by scantron_get_maxbubble(), the 
+       calling routine should trap the error condition and display the warning
+       found in &navmap_errormsg().
+
    Returns the maximum number of bubble lines that are expected to
    occur. Does this by walking the selected sequence rendering the
    resource and then checking &Apache::lonxml::get_problem_counter()
@@ -9384,6 +9596,11 @@ ssi_with_retries()
    Validates all scanlines in the selected file to not have any
    invalid or underspecified student/employee IDs
 
+=item navmap_errormsg() :
+
+   Returns HTML mark-up inside a <div></div> with a link to re-initialize the course.
+   Should be called whenever the request to instantiate a navmap object fails.  
+
 =back
 
 =cut