--- loncom/interface/londependencies.pm	2013/05/03 21:57:13	1.4
+++ loncom/interface/londependencies.pm	2017/08/13 20:52:59	1.5
@@ -2,7 +2,7 @@
 # Handler to manage dependencies for HTML files uploaded directly
 # to a course. 
 #
-# $Id: londependencies.pm,v 1.4 2013/05/03 21:57:13 raeburn Exp $
+# $Id: londependencies.pm,v 1.5 2017/08/13 20:52:59 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -101,8 +101,12 @@ sub handler {
     my $docs_url = $env{'form.url'};
     my $folderpath = &unescape($env{'form.folderpath'});
     my ($mimetype,$numpathchgs,$numrefchanges,%allfiles,%codebase,$url);
+    my $earlyout;
     if ($symb) {
         (undef,undef,$url) = &Apache::lonnet::decode_symb($symb);
+        unless (&Apache::lonnet::is_on_map($url)) {
+            $earlyout = 1;
+        }
     } elsif (($docs_url) && (($env{'httpref.'.$docs_url} ne '') ||
                              ($docs_url =~ m{^\Q/uploaded/$cdom/$cnum/\E(portfolio/syllabus)/}))) {
         $url = $docs_url;
@@ -122,10 +126,18 @@ sub handler {
         ($destination) =
             ($url =~ m{^\Quploaded/$cdom/$cnum/\E((?:docs|supplemental)/(?:default|\d+)/\d+)/});
         $context = 'coursedoc';
+        if ($destination eq '') {
+            $earlyout = 1;
+        } 
     }
     my $js = &Apache::loncommon::ask_embedded_js();
     my $output = &Apache::loncommon::start_page($title,$js,
                                                 {'only_body' => 1});
+    if ($earlyout) {
+        $r->print($output.&mt('Cannot display dependency information - invalid file: [_1].',$url).
+                  &Apache::loncommon::end_page());
+        return OK;
+    }
     if ($action eq 'modifyhrefs') {
         my ($result,$count,$codebasecount) =
             &Apache::loncommon::modify_html_refs('manage_dependencies',$destination,