Index: trunk/kernel/include/category.php
===================================================================
diff -u -N -r3576 -r3828
--- trunk/kernel/include/category.php	(.../category.php)	(revision 3576)
+++ trunk/kernel/include/category.php	(.../category.php)	(revision 3828)
@@ -1506,6 +1506,8 @@
     function SetLastUpdate($date)
     {
     	$parents = $this->Get('ParentPath');
+    	if (!$parents) return false;
+    		
     	$parents = substr($parents, 1, strlen($parents) - 2 );
     	$parents = explode('|', $parents);