Hi David,
The 'P' status is a Posting error. This means that the check was printed but there was some sort of problem when the check was posted. This would explain why you don't find anything in AP or GL. If there is an error batch, it may contain this check. If there are no error batches, it likely was deleted.
This can be cleared by printing the Check Reconciliation report and ensuring that all status are selected - especially the 'Posting Error' status.
This check will have to be re-entered as a non-printed manual check so that it can pay the invoice(s) and get to GL.
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Regards,
Softrak Tech Support