If you installed knoppix by first booting the LiveCD then using kx-hdinstall from terminal, I can giva you a hint.
When booting the live cd, press the F2 and F3 buttons to see the options list, the lang= option is important.
However, the xorgconf or xorgconfig will let you choose a keymap for X
{most forward-thinking distros have dumped Xfree in favor of Xorg}
