SAP Message >2641 - A payment document could not be added to the document buffer

Diagnosis You wanted to add a new entry with ID &V4& for bank &V1&, account &V2&,during printout with sequence number &V3&. This was not possible,because an entry already exists. This entry cannot be made with mass assignment of external check numbersto document numbers. Procedure Check the reason for the error, and after elimination execute programSAPFKPY3 to start a new payment medium run.