Hi,
-- If you are backing up multiple volumes at a time, I would suggest you to do the steps mentioned in the following technote :
How to get Advanced Open File Option to snap one volume at a time during multi-volume backups
http://support.veritas.com/docs/264464
-- If the cache file is being created on a volume that is being backed up, that setting will be ignored. So, while specifying the path for the cache file, do not put it on a volume that is being backed up as a part of that particular backup job. Place it on some other volume.
-- Exclude all *.VSP files from Anti Virus scanning.
-- Look for a *.VSP file on the server. Delete it if found. If the file is not being deleted, a reboot is required.
Re run the backup and observe the results.
Do let me know if the above helped you in resolving the issue.
Should the issue persist, please send the exact error message and the AOFO settings that have been specified.
Thanks.