diff --git a/webtools/bugzilla/process_bug.cgi b/webtools/bugzilla/process_bug.cgi
index 9773dce6d02f..29b9990aecf5 100755
--- a/webtools/bugzilla/process_bug.cgi
+++ b/webtools/bugzilla/process_bug.cgi
@@ -1890,8 +1890,7 @@ foreach my $id (@idlist) {
                     shift @oldlist;
                 } else {
                     if ($oldlist[0] != $newlist[0]) {
-                        $dbh->bz_unlock_tables(UNLOCK_ABORT);
-                        die "Error in list comparing code";
+                        ThrowCodeError('list_comparison_error');
                     }
                     shift @oldlist;
                     shift @newlist;
diff --git a/webtools/bugzilla/reports.cgi b/webtools/bugzilla/reports.cgi
index 947993a56beb..1181e3a81f1a 100755
--- a/webtools/bugzilla/reports.cgi
+++ b/webtools/bugzilla/reports.cgi
@@ -232,7 +232,8 @@ sub chart_image_name {
     # and number
 
     if ($datasets !~ m/^[A-Za-z0-9:]+$/) {
-        die "Invalid datasets $datasets";
+        $vars->{'datasets'} = $datasets;
+        ThrowUserError('invalid_datasets', $vars);
     }
 
     # Since we pass the tests, consider it OK
diff --git a/webtools/bugzilla/template/en/default/global/code-error.html.tmpl b/webtools/bugzilla/template/en/default/global/code-error.html.tmpl
index 0ec46461f852..5081589edd65 100644
--- a/webtools/bugzilla/template/en/default/global/code-error.html.tmpl
+++ b/webtools/bugzilla/template/en/default/global/code-error.html.tmpl
@@ -192,7 +192,10 @@
     [% title = "Invalid Series" %]
     The series_id [% series_id FILTER html %] is not valid. It may be that
     this series has been deleted.
-    
+
+  [% ELSIF error == "list_comparison_error" %]
+    Unexpected error in list comparing code.
+
   [% ELSIF error == "mismatched_bug_ids_on_obsolete" %]
     Attachment [% attach_id FILTER html %] ([% description FILTER html %]) 
     is attached to [% terms.bug %] [%+ attach_bug_id FILTER html %], 
diff --git a/webtools/bugzilla/template/en/default/global/user-error.html.tmpl b/webtools/bugzilla/template/en/default/global/user-error.html.tmpl
index ac1bca1c24ba..5ffae70acc75 100644
--- a/webtools/bugzilla/template/en/default/global/user-error.html.tmpl
+++ b/webtools/bugzilla/template/en/default/global/user-error.html.tmpl
@@ -696,6 +696,11 @@
     The context [% context FILTER html %] is invalid (must be a number,
     "file" or "patch").
 
+  [% ELSIF error == "invalid_datasets" %]
+    [% title = "Invalid Datasets" %]
+    Invalid datasets <em>[% datasets FILTER html %]</em>. Only digits,
+    letters and colons are allowed.
+
   [% ELSIF error == "invalid_format" %]
     [% title = "Invalid Format" %]
     The format "[% format FILTER html %]" is invalid (must be one of