Diagnosis
An internal error has occurred. More than one &V2& partners were foundfor contract &V1&.

System Response
Processing is canceled.

Procedure
Contact SAP with the following error message:
The partner data must be checked. The system determined in part 1 ofmodule ISU_BILLING_PREPARE_UPDATE that more than one partner was foundfor one contract. The structure reader in function moduleISU_CUSTOMER_DATA_READ must provide exactly one partner.