Hello All, I am trying to submit the same tasks (by checking batch action checkbox) from K2workspace worklist webpart  one after other from different IE windows. First one completes fine, while completing the second one, it gives error "Worklist item is invalid or no longer present" which is expected func fRefer attachment]. But when i tried the same thing from Sharepoint embedded worklist webpart, it submits both the tasks which is diferent from K2workspace worklist webpart. Is it a bug. Please test the same from ur end.