cloop error can be indicative of a bad cd.

1)Check the md5sum of the .iso you burned.

2)Boot like this:

boot: testcd

If it passes w/ testcd then boot like this:

boot: failsafe

If it boots w/ failsafe it would seem that it doesn't like something about your hardware. Try using the cheat codes to narrow it down.

boot: knoppix noscsi nopcmcia

for example.

Also you can boot like this:

boot: knoppix 2

Then do this:

dmesg | less

lspci -v

Look for errors, IRQ conflicts and anything else that might tell you what's going on.