Hello,
Please check,whether the device that you are using is there in our Hardware Compatibility List.
Kindly refer the following document for the same:
Symantec Backup Exec for Windows Servers (tm) 10d (10.1) Hardware Compatibility List. Includes HCL information for supported drives, libraries, virtual tape devices, fibre-channel HBAs, switches, routers/bridges, and iSCSI components. For printing purposes, the latest version of Acrobat is recommended
http://support.veritas.com/docs/281670
Thank You,
Shweta