Diagnosis
An internal error has occurred.

System Response
Processing is canceled.

Procedure
INCLUDE ISU_SAP OBJECT DOKU ID TX
Provide the following error message:
The system determined in part 1 of module ISU_BILLING_PREPARE_UPDATEthat field &v1& is not filled. &v1& must be filled in function moduleISU_DATA_DETERMINE_FROM_INSTL in ISU_TRIGGER_BILLABLE_CHECK.