Kindly refer the the following technote link and revert back with the result of the same.
Title:- What is the retension feature in VERITAS Backup Exec for Windows Servers, and what is it used for?
http://seer.support.veritas.com/docs/191452.htm
Also,
Title:- How to determine the cause of a Tape Alert (Hardware) message that is reported in the Backup Exec job log
http://seer.support.veritas.com/docs/230206.htm
We hope this helps. Let us know if the problem still exists and revert back with the error message.