0xa00084ec - error reading/writing data from/to the media
The "Cyclic Redundancy Check" (CRC) error is generic in nature and can be caused by numerous factors. Following TechNote would be useful to understand the possible reasons of CRC errors.
http://seer.support.veritas.com/docs/192216.htm
Here are a few suggestions that will help you.
1 Update SCSI drivers. 2 Clean the tape drive using cleaning media. (3 to 4 times) 3 Try running hardware diagnostic utility on the tape drive. 4 Try performing backup on a fresh media (New Media). 5 Install latest Backup Exec device drivers from the following link:
http://seer.support.veritas.com/docs/273853.htm
To isolate the cause of problem, perform a test backup with Windows native backup utility NTBACKUP and verify the result.
Note: Note: Stop all the Backup Exec services prior to performing backup with NTbackup. Revert back with the result of NT backup.