OK, the point with SharePoint is solved. Thanks to Cancom Mr. Schmid.http://helpcenter.veeam.com/backup/80/e ... sions.html
The problem was, that the sharepoint VM is in the perimeter network and the database in the LAN.
For the guest processing, I used the admin from perimeter domain which have no rights in the LAN
or the sql server. Now I used for guest processing the SharePoint Farm administrator from the
LAN which also have rights in the perimeter domain and it works.