--- loncom/interface/domainprefs.pm	2008/07/08 03:04:23	1.61
+++ loncom/interface/domainprefs.pm	2008/07/09 21:34:27	1.62
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Handler to set domain-wide configuration settings
 #
-# $Id: domainprefs.pm,v 1.61 2008/07/08 03:04:23 raeburn Exp $
+# $Id: domainprefs.pm,v 1.62 2008/07/09 21:34:27 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -41,6 +41,7 @@ use LONCAPA;
 use LONCAPA::Enrollment;
 use File::Copy;
 use Locale::Language;
+use DateTime::TimeZone;
 
 sub handler {
     my $r=shift;
@@ -4208,8 +4209,7 @@ sub modify_defaults {
             }
         } elsif ($item eq 'timezone_def') {
             if ($newvalues{$item} ne '') {
-                my @timezones = &DateTime::TimeZone->all_names;
-                if (!grep(/^\Q$newvalues{$item}\E/,@timezones)) {
+                if (!DateTime::TimeZone->is_valid_name($newvalues{$item})) {
                     push(@errors,$item);   
                 }
             }