I'm in somewhat the same boat here, using knoppix 3.4 with kernel 2.4.26 and trying to install the nvidia drivers. I didn't try the NVIDIA shell script from nvidia.com first, am trying to go "the debian way" and more or less follow the README in /usr/share/doc/nvidia-kernel-source. Since (#1 method) I couldn't find a matching kernel-headers package for 2.4.26 (from uname -r) but only 2.4.26-1, I'm going with a full kernel rebuild and reinstall I guess.

I apt-get installed "nvidia-kernel-source knvidia-kernel-common kernel-source-2.4.26". I installed and applied the 'debian-kernel-patch-2.4.26' and 'kernel-patch-preempt-2.4' pkgs, copied over the .config from /boot/config-2.4.26 to /usr/src/linux/.config (/usr/src/linux sym links to new kernel source). I ran 'make menuconfig' and am doing 'make-kpkg kernel_image' now and waiting... I'll let you know how it turns out.

Isn't there a better way to do this? Anyone else have better luck or ever try 'knx-live-inst' to install nvidia before an hdinstall?