Index: branches/5.1.x/core/units/helpers/search_helper.php
===================================================================
diff -u -N -r14241 -r14528
--- branches/5.1.x/core/units/helpers/search_helper.php	(.../search_helper.php)	(revision 14241)
+++ branches/5.1.x/core/units/helpers/search_helper.php	(.../search_helper.php)	(revision 14528)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: search_helper.php 14241 2011-03-16 20:24:35Z alex $
+* @version	$Id: search_helper.php 14528 2011-09-16 15:11:42Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -459,7 +459,7 @@
 			}
 
 			$custom_filters = unserialize($custom_filters);
-			if (!array_key_exists($grid_name, $custom_filters)) {
+			if (!is_array($custom_filters) || !array_key_exists($grid_name, $custom_filters)) {
 				// filters not defined for given grid
 				$cache[$cache_key] = false;
 				return false;