diff --git a/application/modules/requests/models/StackModel.php b/application/modules/requests/models/StackModel.php
index 3cd46af9f0ce75872dbddec643af74955e107848..429b86cb9c32f40902387f35010def9b5d378a77 100644
--- a/application/modules/requests/models/StackModel.php
+++ b/application/modules/requests/models/StackModel.php
@@ -53,6 +53,9 @@ class Requests_StackModel extends Unl_Model
 
         $stacks = new Unl_Model_Collection(__CLASS__);
         foreach ($stackIds as $requestId => $stackId) {
+            if (!$stackId) {
+                continue;
+            }
             $stacks[$requestId] = Unl_Model_Registry::getInstance()->get(__CLASS__, $stackId);
         }
         return $stacks;