Hi there,
Does your tape drive show up correctly in BE if you go to Devices? Have you run the Device Wizard to see if there isn't an issue with your drive?
What hardware is it? If it's an autoloader, ir should be showing the drive below the robotics. The Device Wizard does allow you to reassign the drive with the robotics if need be (Tools --> Device Wizard).
You can also check and make sure that Removable Storage isn't started up for some reason, as this causes issues.
Finally, you can:
1. RUn the driver install from within Backup Exec itself again to reapply the drivers;
2. Restart the services after scanning for hardware changes in Device Manager in Windows.