I think you'll have to do a complete re-install. Of course, back up /home first: if you've been wise, this is on a seperate partition or drive anyway.....

Upgrading in one hit is pretty dangerous in Knoppix, which isn't to say upgrading is impossible. There are no guarantees that things won't break. You may find Kanotix more amenable to upgrades than Knoppix.

First, get apt-spy. Point all your sources at unstable. (Remember that there are dangers in running unstable........ )

apt-get update and then try updating Kde first. No guarantees. At your own risk! Putting your head in the mouth of the Krokodile, etc. etc.

If this works, everything else should be relatively straightforward.

Good luck!