ntbackup not seeing ait tape drive

ntbackup fails to see ait tape drive
Platform Compaq ML370 raid server g2 ait 50g tape drive running nt4.0 sp6
Problem: ntbackup will not recognize tape drive even though it is seen at bootup and in control panel(scsi adapters and tape devices were it shows drivers loaded), the ntbackup window will just sit there with the hour glass and no error messages are given, you need to go into task manager to end the task. Loaded latest drivers from Compaq, tape and adapter (which is onboard). All hardware has been replaced
including system board. Compaq support feels it is a s/w issue with ntbackup???? Any other suggestions besides a full reload.

Thanks
Tom