Transaction ME22n(Update wa terminated)

When iam trying to Delete a particular PO number,it shows a message that it has been deleted but when i go back it gives a message in my inbox that update was terminated(in the error section i see error in update of vbep table).i have tries debugging it several times i do not know how to get hold of the code when the mail is being sent or when the update is being done.

Please help me on this.