--- loncom/interface/lonprintout.pm	2017/01/30 19:47:54	1.627.2.20
+++ loncom/interface/lonprintout.pm	2018/09/02 16:36:29	1.627.2.23
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # Printout
 #
-# $Id: lonprintout.pm,v 1.627.2.20 2017/01/30 19:47:54 raeburn Exp $
+# $Id: lonprintout.pm,v 1.627.2.23 2018/09/02 16:36:29 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -890,7 +890,7 @@ sub include_pdf {
     my $londocroot = $Apache::lonnet::perlvar{'lonDocRoot'};
     $file =~ s{(.*)/res/}{$londocroot/res/};
 
-    open(FILE,">>$Apache::lonnet::perlvar{'lonPrtDir'}/$env{'user.name'}_$env{'user.domain'}_printout.dat");
+    open(FILE,">>","$Apache::lonnet::perlvar{'lonPrtDir'}/$env{'user.name'}_$env{'user.domain'}_printout.dat");
     print FILE ("$file\n");
     close (FILE);
 
@@ -1961,7 +1961,7 @@ sub latex_corrections {
 	$result =~ s/(\\end\{document})/\\strut\\vspace\*{-4 mm}\\newline $copyright $end_of_student $1/;
     }
     $result =~ s/\$number_of_columns/$number_of_columns/g;
-    $result =~ s/(\\end\{longtable}\s*)(\\strut\\newline\\noindent\\makebox\[\\textwidth\/$number_of_columns\]\[b\]{\\hrulefill})/$2$1/g;
+    $result =~ s/(\\end\{longtable}\s*)(\\strut\\newline\\noindent\\makebox\[\\textwidth\/$number_of_columns\]\[b\]\{\\hrulefill})/$2$1/g;
     $result =~ s/(\\end\{longtable}\s*)\\strut\\newline/$1/g;
 #-- LaTeX corrections     
     my $first_comment = index($result,'<!--',0);
@@ -3458,7 +3458,9 @@ ENDPART
         if ($env{'request.enc'}) {
             $url = &Apache::lonenc::encrypted($url);
         }
-        $URLback = $url.($url =~ /\?/) ? '&amp;':'?'.'symb='.$helper->{VARS}{'symb'};
+        if ($url ne '') {
+            $URLback = $url.(($url =~ /\?/) ? '&amp;':'?').'symb='.$helper->{VARS}{'symb'};
+        }
     }
     #
     # Final adjustment of the font size: