We have a similar problem from time to time with AP-A and exiting--creates an access violation error.  Our CFO was in editing a vendor and went to exit out after saving and it gave her an access violation.  She said it also didn't save the changes she made - she printed a check for the vendor and it still contained the old info (maybe she didn't save, or it gave her the AV upon saving, sometimes users get confused). So she just did a manual check (I would have tried going back into the record and trying again, but that's just me).