Please let us know what kind of Backup job operation are you trying to perform, please elaborate if itâs Local or Remote system backup or an Exchange or SQL backup?
In order to troubleshoot the problem, kindly refer the following technote link.
Title:- "Unable to attach to one of the drives" error is reported while backing up remote systems
http://seer.support.veritas.com/docs/259874.htm
Title:- "Unable to attach to one of the drives" (a000848c HEX or e000848c HEX) is reported when a job fails
http://seer.support.veritas.com/docs/266177.htm
We hope this helps.Let us know if the problem still exists and revert back with the error message.