Why don't you try replacing the AppleNforceATA.kext with the the AppleVIAATA.kext during installation as I suggested in my previous post?
Unfortunately I don't have a nforce4 chip MB, so you will have to try it out yourself.
Good luck! :-)

edit: that is, if you get to the installer...if you're not, try the whole procedure. I also read that the previous version of Medevil's AppleNforceATA.kext (1.0.2 I think) works. But i can't find it, so I can't confirm it works on my nforce3.