The i found this one here:

A product installer – possibly from a 3rd party app has registered that file as being required for a System State backup and not then removed the registration from the System State when the file was removed.

Either identify the vendor of the file and speak to them about a fix – or create a file with the same name in the same folder. Note it is unlikely that you will need the specific file for a restore (assuming your server does restart correctly currently)

So, to have a short break fix, just create a dummy file OR contact the vendor of the driver/program.

Microsoft KB955078 Volume Shadow Copy Service (VSS) System Writer backup fails, and error messages reference nonexistent files in Windows Server 2008

Symantec had a KB entry, but the removed it.. i found it in the Google cache:

——————————

Document ID: 303664
http://support.veritas.com/docs/303664 E-Mail this document to a colleague

System State backup of a Windows 2008 server completes with an exception

Exact Error Message
Backup- System?State System?State
VSS Snapshot warning. File [PATH] [FILENAME] is not present on the snapshot.

Details:

System State backup of a Windows 2008 server may complete with the above mentioned exception if a driver file(s) was deleted/renamed. For example in the Figure 1, 04mmdat.sys is causing the exception.

Volume Shadow Copy Service (VSS) System Writer may list a file to be backed up even though the file is no longer present on the server. View the {GUID}-System_Writer.xml file located in the directory C:\Program Files\Symantec\Backup Exec\Logs to confirm if the writer lists the file present as an exception in the job log.
NOTE:
The exception can be safely ignored as it does not affect the functionality of the Backup set.
Workaround:
Follow the steps listed below:
1. Create a empty text file with the same name as the file mentioned in the exception
2. Place the document in the same location as in the exception
Resolution:
For more details on resolution refer to the following article from Microsoft:
http://support.microsoft.com/kb/955078

Supplemental Material:

System: Ref.#
Description

ETrack: 1264044
VSS Snapshot exceptions happen during system state backup if tape drivers were deleted

Acknowledgements
Microsoft

——————————