I had a similar problem with my Panasonic 8123 until I realized that I was using the wrong IDE cable. Check out if this is your problem as well; you should be using a 40 Conductor cable (each of the wires in the ribbon is slightly larger than 1mm).
80 Conductor IDE cable -> doesn't work
40 Conductor IDE cable -> works great
Both of those can plug into the same 40-pin IDE slot on the Motherboard.