Hi Paul,
Because this is a case of interuppted posting, you will most likely want to discuss this with your Partner as the transactions might need to be cleaned up in your SQL database. When a user performs transaction-level posting a record is created in the company database under the SY00500 table. The batch ID will be the User ID of the GP user who was attempting to post the transaction. This record will need to be removed from the table and the associated AP and AR tables will need to be examined to see if the transactions posted correctly.