SAP Message 26045 - Document & is locked by &

Diagnosis
You want to create or change a document.
One of the following situations triggered this error message:
This document is currently being created or edited by user &V2&.
This document has just been processed, but the system has not yetupdated the document.
An object master record (such as material master) is currently beinglinked to this document, or the link is being maintained.
The change master record entered in the document is currently beingmaintained.

Procedure
Try again later to process the document, or ask user &V2& why thedocument is locked.