Auto invoice import program&...

Auto invoice import program is getting erred out with below error message 

Errors:   1) Invalid bill to customer reference (ORIG_SYSTEM_BILL_CUSTOMER_REF) ((Null))
            2) The Bill To address reference must exist in Oracle Receivables, and it must be assigned to the Bill To customer
               (ORIG_SYSTEM_BILL_ADDRESS_REF) ((Null))

We are using a custom program to pouplate the ra_interface_lines table and we never used to populate ORIG_SYSTEM_BILL_CUSTOMER_REF value. the program was working fine. but now its giving this error

Any one has faced this issue before