Hello,
We would like to you follow the steps shown in the following technote:
How to troubleshoot the error "A failure occurred querying the Writer status" (a000fed1 HEX or e000fed1 HEX) using VSSADMIN
http://support.veritas.com/docs/261993
Try running the separate backup of "shadow copy components" and let us know the result.
To isolate the issue please perform the backup using Windows NTbackup utility and let us know the results.
Thank You,
Shweta