Kindly apply Service Pack 1 and verify the result.
You may download Service Pack 1 from the link mentioned below:-
Title:- VERITAS Backup Exec (tm) 9.1 for Windows Servers revision 4691 - Service Pack 1 http://seer.support.veritas.com/docs/267180.htm
You may refer the following document to ensure SP1 is loaded.
Title:- How to ensure that Service Pack 1 has been applied to VERITAS Backup Exec (tm) 9.1 for Windows Servers revision 4691 http://seer.support.veritas.com/docs/267690.htm
We hope this helps. Let us know if the problem still exists and revert back with the error message.