nvidia nforce drivers ARE for audio, and the onboard NIC
I had to install them for my MSI K7N2D motherboard...
The nvidia page says that you may have to compile and install
the kernel.tar.gz file if you have a custom kernel...
I dont know much about knoppix, but it may be that the kernel
is nonstandard and you may need to use the alternate install
method:
the install instructions are located here:
http://download.nvidia.com/XFree86/n..._1.0-0261.html