a while back I was able to start an NIS server and get Knoppix network clients loading with the login screen but I don't have all the details. From what I remember, just starting kdm did most of the trick as far as getting a login screen goes.

try booting into runlevel 3 and then run 'xinit -e `which kdm`

1) boot prompt: knoppix 3
2) console prompt: xinit -e `which kdm`