Hi,
Thank you for posting your query,
We would suggest you to install Hotfix #47 and service pack 2 to resolve this issue :
Service Pack 2 for Backup exec v9.1
http://support.veritas.com/docs/275247
Hotfix #47 :
http://support.veritas.com/docs/275354
We hope this information helps, if you have any other questions please respond to the post and we will be more than happy to assist you further.