To find out whether you've entered Accounts Payable as the allocation account on a purchase, click the Purchases tab in the Transaction Journal window and enter a date range to include all possible transactions.
Look for any purchases transactions in the scrolling list that debit and credit the Accounts Payable account and aren't used as historical purchases or as transactions that settle debits.
If this is the case and you have a changeable data file, you can display the purchase and edit the allocation account to the correct account. If you have an unchangeable data file you can reverse the transaction and reenter it with the proper allocation account.