Fixes:Uncaught type Error led to cause the Internal Server Error

modules/Events/models/Module.php

@@ -29,7 +29,7 @@ class Events_Module_Model extends Calendar_Module_Model {
         $recordModel = parent::saveRecord($recordModel);
         
         //code added to send mail to the vtiger_invitees
-        $selectUsers = $recordModel->get('selectedusers');
+        $selectUsers[] = $recordModel->get('selectedusers');
         if(!empty($selectUsers))
         {
             $invities = implode(';',$selectUsers);