Index: branches/5.2.x/core/units/categories/categories_event_handler.php
===================================================================
diff -u -N -r15012 -r15016
--- branches/5.2.x/core/units/categories/categories_event_handler.php	(.../categories_event_handler.php)	(revision 15012)
+++ branches/5.2.x/core/units/categories/categories_event_handler.php	(.../categories_event_handler.php)	(revision 15016)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: categories_event_handler.php 15012 2012-01-06 20:38:49Z alex $
+* @version	$Id: categories_event_handler.php 15016 2012-01-09 10:27:49Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -293,7 +293,7 @@
 				}
 			}
 
-			if ($event->getEventParam('parent_cat_id') !== false) {
+			if ( (string)$event->getEventParam('parent_cat_id') !== '' ) {
 				$parent_cat_id = $event->getEventParam('parent_cat_id');
 
 				if ("$parent_cat_id" == 'Root') {
Index: branches/5.2.x/core/kernel/db/cat_event_handler.php
===================================================================
diff -u -N -r15012 -r15016
--- branches/5.2.x/core/kernel/db/cat_event_handler.php	(.../cat_event_handler.php)	(revision 15012)
+++ branches/5.2.x/core/kernel/db/cat_event_handler.php	(.../cat_event_handler.php)	(revision 15016)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: cat_event_handler.php 15012 2012-01-06 20:38:49Z alex $
+* @version	$Id: cat_event_handler.php 15016 2012-01-09 10:27:49Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -600,7 +600,7 @@
 
 		// add category filter if needed
 		if ($event->Special != 'showall' && $event->Special != 'user') {
-			if ($event->getEventParam('parent_cat_id') !== false) {
+			if ( (string)$event->getEventParam('parent_cat_id') !== '' ) {
 				$parent_cat_id = $event->getEventParam('parent_cat_id');
 			}
 			else {