Hey,
sorry for my late answer.
Thak you very much for your answer. The problem doesn't seem to be caused by Symantec BE10.
Parallel with the BE10 - backup we do a VM-Ware backup (auto creating Snapshots with another server). The technician who had installed this said that he has this error with some other companys, too. (So he can fix it)
The backup with Symantec failed, because the Vbackup (VM-Ware) was trying to take a snapshot over and over without any success.
Kind regards,
Tobias