SAP Message BEA283 - Billing item for item &1 of transaction &2 not available

Diagnosis
Billing due list item &SYST-MSGV2&/&SYST-MSGV1& is to be billed usingdifference calculation. The billing item for which the differenceshould be calculated cannot, however, be read.

System Response
The billing due list item cannot be billed.

Procedure for System Administration
The cause for this is probably a program error or data inconsistency.