WSUS problem in VSS saveset

Hi all,

We have a Windows 2008 server (x64) with WSUS installed.
On this server, a NetWorker 7.4.4 client is installed.

During the backup, I recieve the following error:
F:\WSUS\
F:\WSUS\UpdateServicesDbFiles\
Windows Internal Database - Get file attributes returned error 123 for VSS file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\WSUS\\UpdateServicesDbFiles
Windows Internal Database - Error saving file path F:\WSUS\\UpdateServicesDbFiles that is associated with Shadow Copy path \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\WSUS\\UpdateServicesDbFiles. The filename, directory name, or volume label syntax is incorrect.

Windows Internal Database - Warning: Failed to save connecting dir \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\WSUS\\UpdateServicesDbFiles
Windows Internal Database - Get file attributes returned error 123 for VSS file \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\WSUS\\UpdateServicesDbFiles\SUSDB.mdf
Windows Internal Database - Error saving file path F:\WSUS\\UpdateServicesDbFiles\SUSDB.mdf that is associated with Shadow Copy path \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy28\WSUS\\UpdateServicesDbFiles\SUSDB.mdf. The filename, directory name, or volume label syntax is incorrect.

Windows Internal Database - ERROR: Failed to save FileGroup files, writer = SqlServerWriter
Windows Internal Database - Error saving writer Windows Internal Database
Windows Internal Database - ERROR: Aborting backup of saveset VSS SYSTEM SERVICES: because of the error with writer Windows Internal Database.
Windows Internal Database - Error saving
7162:(pid 984): save of VSS SYSTEM SERVICES:\ to bvault01 failed


The WSUS DB is installed on the F-drive, so this should be OK.
I've already tried to add the "VSS:sqlsystemwriter=off" and "VSS:*=off" as save operations, but because it's a W2K8 server this is not possible:

43705:(pid 984): Save Operations value is ignored on this OS platform.