My mistake, I assumed it was because of the error message
Check Device Manager, is the device recognized correctly? Open its properties and check the driver vendor. It should be symantec. If it's not stop all BE services and run tapeinst.exe to install Symantec drivers for the tape drive.
Double-check that the tapes and the drive match. Download the latest firmware from IBM and do a firmware upgrade on the drive. Check the troubleshooting portion of the tape drive manual and look for what the flashing light might mean.
If after all this it still doesn't work, I believe you're looking at a hardware failure