I had this problem (cant find knoppix filesystem, sorry) when booting 5.0.1 from the CD at my old computer (p2-600). The problem didnt appear on the newer AMD-64-3000+. SO I dont think it is a burning problem ( I used a CD-R).

I solved this problem using ..

... "failsafe" for booting. But then my mouse (ps2 and serial) didnt move anymore.

... "knoppix nodma". But then the system wasn't stable.

... the boot-command "knoppix noapci apci=off pci=bios" that is mentionend on the boot-up-screen (Key F2 or F3) for bad BIOS'. Check the spelling, I didn't learned it by heart. This one works well.