Balance Foward Billing Program does not generate in BPA - COmpletes with Warning

In Vision Instance 12.1.3,  I completed all the setups for BFB in Recivables R12.1.3 for test purpose. Created Invoices for the sites. I used BFB at Account level as well as Site level.

When I kicked the program "Generate Balance forward Bills" It printed all transactions on one sigle document in Draft Mode". It only gherated some drft Bills very first time.

But then I created more Invoices and more customers. Completed the Steups. Then I ran the "Generate Balance forward Bills" Program . The "BPA Balance Forward Bill Print Program (Multiple Languages)" completes with Warning. Now It does not generate even in Draft or Final Mode.