You did not mention which Knoppix distro failed, but that error looks like an error that is hit-or-miss, depending on the computer hardware combination.

I found Knoppix 3.7 did not work on HP Pavilion ze4041, but Knoppix 3.8 did work. I have also found that Mepis worked on the HP (but I do not like the Mepis desktop, so I am switching... PCLinuxOS is pretty cool).