Oracle Workflow issue - Notifications Failing With Error_stack= Wf_object_cache.Getobject(Oracle.App

Hi All,

Can anyone help me with the below issue.

Error Message		ORA-21710: argument is expecting a valid memory address of an object
Error Stack		WF_OBJECT_CACHE.GetObject(oracle.apps.wf.notification.send) WF_BES_CACHE.GetEventByName(oracle.apps.wf.notification.send) Wf_Notification.SendSingle(VALERIE.CHIAM, XXAPINV1, CODING APPROVAL, 20-OCT-2011, WF_ENGINE.CB) Wf_Notification.Send(VALERIE.CHIAM, XXAPINV1, CODING APPROVAL, 20-OCT-2011, WF_ENGINE.CB) Wf_Engine_Util.Notification_Send(XXAPINV1, 19636, 202849, XXAPINV1:CODING APPROVAL) Wf_Engine_Util.Notification(XXAPINV1, 19636, 202849, RUN)

We have recently migrated our custom workflow to Test instance. While creating the invoices notifications are being sent to the users and workflow is erroring out with the above error. When we are retrying the workflow the error is cleared and workflow is active. But sometimes the error still remains. Its happening to all the invoices which are created.