This is had been resolved about 7 months months ago but I have forgotten it. I've seen that more than 400 have viewed this post. It seem to me that a lot of people are having this problem.

This is actually a hardware problem. In my case this was due to the modulator that I use to connect to videoout to connect to a TV. There was a 75ohms resistor connect at the video input of the modulator which seems to affect the video card.

The simplest solution is to disconnect the modulator when running knoppix. When connecting directly to TV videoin, this issue occurs on some set but not to other.

Hope this may be helpful.

I have just upgraded to knoppix 5.0.1 and able to install nvidia driver again in this new setup.