SAP Message >0500 - Program error: Rounding called for inpermissible document

Diagnosis
The amount of a collective bill item or an installment plan item has tobe rounded off. Amount changes to items like this are not permitted,however, since they would then no longer match the underlying originalreceivables.

System Response
Error message

Procedure
INCLUDE NA_SYSADMIN1 OBJECT DOKU ID TX

Procedure for System Administration
INCLUDE FICA_NA_OSS OBJECT DOKU ID TX