Try repeating this when system just at the BIOS. If it still spits out the tapes (and you are 100% sure you have the right kind of tape drive), then the tape mechanism is bad. You know this because when the host is at the BIOS, the eject isn't possibly a function of any application software.
Also, you can look at some diagnostic software that will give you error info, google tapealert as this is the name of the spec, and you can probably find some software.