--- loncom/homework/lonhomework.pm	2006/06/30 17:42:38	1.256
+++ loncom/homework/lonhomework.pm	2006/07/20 03:57:38	1.257
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # The LON-CAPA Homework handler
 #
-# $Id: lonhomework.pm,v 1.256 2006/06/30 17:42:38 albertel Exp $
+# $Id: lonhomework.pm,v 1.257 2006/07/20 03:57:38 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -514,8 +514,9 @@ sub due_date {
     my $due_date= &Apache::lonnet::EXT("resource.$part_id.duedate",$symb,
 				       $udom,$uname);
     &Apache::lonxml::debug("looking for due_date $part_id $symb $due_date");
-    if (defined($interval)) {
+    if ($interval =~ /\d+/) {
 	my $first_access=&Apache::lonnet::get_first_access('map',$symb);
+	&Apache::lonxml::debug("looking for first_access $first_access");
 	if (defined($first_access)) {
 	    $interval = $first_access+$interval;
 	    $date = ($interval < $due_date)? $interval : $due_date;