Index: branches/5.1.x/core/units/categories/categories_event_handler.php
===================================================================
diff -u -N -r14241 -r14320
--- branches/5.1.x/core/units/categories/categories_event_handler.php	(.../categories_event_handler.php)	(revision 14241)
+++ branches/5.1.x/core/units/categories/categories_event_handler.php	(.../categories_event_handler.php)	(revision 14320)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: categories_event_handler.php 14241 2011-03-16 20:24:35Z alex $
+* @version	$Id: categories_event_handler.php 14320 2011-05-20 07:57:32Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -1595,7 +1595,7 @@
 				$object->SetError('Template', 'no_inherit');
 			}
 
-			if (!$this->Application->isAdminUser) {
+			if ( !$this->Application->isAdminUser && isset($object->VirtualFields['cust_RssSource']) ) {
 				// only administrator can set/change "cust_RssSource" field
 
 				if ($object->GetDBField('cust_RssSource') != $object->GetOriginalField('cust_RssSource')) {