Diagnosis
The system tried to copy theofficial document numberfrom another billing document, &V1&, but the document does nothave one.

Procedure
With some billing documents, the system does not generate an officialdocument number until you print it. If this is the case, make sure thatthe original billing document has been printed out.
If that does not work, reverse the original billing document and createa new one.
If the system still fails to generate an official document number for it
, contact your system administrator.

Procedure for System Administration
Check the Customizing settings for official document numbering in theIMG activity Define Document Classes.