SAP Message UR777 - Program error in extractor -> see long text

Diagnosis
A program error has occurred in the extractor. Processing cannot becontinued.

System Response
Das Programm wurde abgebrochen.

Procedure
Call up OSS and search for notes on error message UR777, Theproblem may already be known. If you are still unable to solve theproblem, create an error message.
Further information:
MSGV1: "&V1&"
MSGV2: "&V2&"
MSGV3: "&V3&"
MSGV4: "&V4&"