Posting accounbting document with RERAPP transaction

I have an assignment to write a program which will read a spreadsheet from the user's computer, and post a condition in flexible real estate for each line in that spreadsheet. That part was fairly easy and I have it working. My problem is that after posting the condition successfully we would like to call the RERAPP transaction to post the accounting document/invoice related to the condition. I have code to call RERAPP with "Call Transaction" and it works partially, but not completely. The problem is that when it does the call Transaction, it executes the transaction and returns with sy-subrc = 0, yet it has not posted the accoounting document, nor has it changed the status on the new condition to indicate that it posted.

Executing RERAPP myself interactively, it works correctly and posts the accounting document. Using debug I can tell that it calls BAPI_ACC_DOCUMENT_POST when I do it that way. When I run my program though, it doesn't call that function module.

Does anybody out there have an idea what might cause this?