Inserting a DVD-ROM on Powerbook Firewire Crashes the System


I've been having a problem, off and on, with my Powerbook Firewire model when I load a CD or DVD into the DVD-ROM drive. In both OS 9.x and 10.x as soon as I close the drive with a disk in it, it does one of three things:

1. Crashes the computer immediately.
2. Spins madly, slows down, spins madly, slows down... I can eject the disk by pressing the button on the side of the drive, but the disk never mounts.
3. Same as 2, but after not mounting, the system is in that semi-frozen state where I can move the mouse around, but nothing happens when I click on it...basically a crash too.

Now, what's weird is that if I do a hardware reset, I can sometimes get the drive to mount correctly, and I can usually get a CD to boot - if I select it in the Start-Up Disk Panel. However, this usually only works for one disk at a time. Take the one out that worked, insert another, repeat step 1, 2 or 3...

Has anyone experienced this? I've had the computer for almost a year now. It started acting up about six-months ago, called apple support, paid the $50, and after the tech walking me through the hardware reset - everything seemed to be going ok, so I said thanks and goodbye (didn't want to lose my PBook for more than a week)

Also, Tech-Tool doesn't find anything wrong, neither does the Hardware Test CD (both after having to use method described above to get the CDs to mount).

If you've got a work around, software, or hardware fix, please tell me what it is.