Index: temp/trunk/html/shopping/payment.php
===================================================================
--- temp/trunk/html/shopping/payment.php	(revision 6679)
+++ temp/trunk/html/shopping/payment.php	(revision 6680)
@@ -56,5 +56,9 @@
 
 sfprintr($objCartSess->getCartList());
-
+foreach($objCartSess->getCartList() as $key => $val){
+	if($val['quantity'] === 0){
+		sfprintr("error");
+	}
+}
 
 switch($_POST['mode']) {