diff -urp old/workflow_ng/workflow_ng/workflow_ng_ui.module new/workflow_ng/workflow_ng/workflow_ng_ui.module
--- old/workflow_ng/workflow_ng/workflow_ng_ui.module	2008-07-17 15:48:06.359375000 +0300
+++ new/workflow_ng/workflow_ng/workflow_ng_ui.module	2008-07-17 15:47:14.093750000 +0300
@@ -1262,11 +1262,14 @@ function workflow_ng_ui_event_get_argume
 
   $event = workflow_ng_get_events('all', $cfg['#event']);
   _workflow_ng_element_defaults($event);
-  $argument_info = $event['#arguments'];
-
+  $argument_info = array();
+  if (!empty($event['#arguments'])) {
+    $argument_info = array($event['#arguments']);
+  }
+  
   //get the arguments provided by an action before
   $configurations = workflow_ng_event_get_configurations($cfg['#event']);
-  $argument_info += workflow_ng_get_new_arguments($configurations, $cfg['#name']);
+  $argument_info = $argument_info + workflow_ng_get_new_arguments($configurations, $cfg['#name']);
 
   $cache[$cfg['#name']] = $argument_info;
   return workflow_ng_ui_event_get_argument_info($cfg, $element);