--- loncom/localize/lonlocal.pm	2008/07/02 21:10:41	1.46
+++ loncom/localize/lonlocal.pm	2008/07/02 21:31:32	1.47
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Localization routines
 #
-# $Id: lonlocal.pm,v 1.46 2008/07/02 21:10:41 raeburn Exp $
+# $Id: lonlocal.pm,v 1.47 2008/07/02 21:31:32 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -293,6 +293,14 @@ sub locallocaltime {
     if (!defined($thistime) || $thistime eq '') {
 	return &mt('Never');
     }
+    if (($thistime < 0) || ($thistime eq 'NaN')) {
+        &Apache::lonnet::logthis("Unexpected time (negative or NaN) '$thistime' passed to lonlocal::locallocaltime");  
+        return &mt('Never');
+    }
+    if ($thistime !~ /^\d+$/) {
+        &Apache::lonnet::logthis("Unexpected non-numeric time '$thistime' passed to lonlocal::locallocaltime");
+        return &mt('Never');
+    }
 
     my $dt = DateTime->from_epoch(epoch => $thistime)
                      ->set_time_zone(&gettimezone());