--- loncom/homework/grades.pm	2008/02/04 17:45:07	1.506
+++ loncom/homework/grades.pm	2008/02/04 23:30:05	1.507
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # The LON-CAPA Grading handler
 #
-# $Id: grades.pm,v 1.506 2008/02/04 17:45:07 raeburn Exp $
+# $Id: grades.pm,v 1.507 2008/02/04 23:30:05 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -5524,6 +5524,10 @@ sub scantron_validator_positional {
     # If the split only gives us one element.. the full length of the
     # answer string, no bubbles are filled in:
 
+    if ($answers_needed eq '') {
+        return;
+    }
+
     if (length($array[0]) eq $$scantron_config{'Qlength'}*$answers_needed) {
         for (my $ans=0; $ans<$answers_needed; $ans++ ) {
             $record->{"scantron.$ansnum.answer"}='';