Might check to see if there's a firmware update for that drive. I've had problems with CD Burners on promise controllers, I would bet the problem is exactly what you think it is. It sees the zip drive as a regular drive, and is trying to detect just what kind of drive it is (and it can't, without a zip disk in there). If there's no fix for it, I'd either always leave a disk in, or move it to one of the motherboard ide controllers. It would probably be ok with the DVD, as long as you don't plan on copying direct from the dvd drive to the zip drive much (and even if you do, I doubt the zip drive is fast enough for you to tell the difference).