I'm just writing this with the Knoppix 3.4 c't edition (subscribers get the c't today). It booted with no problems on my Dell PC.
uname -a
Linux Knoppix 2.6.1 #1 SMP Thu Jan 15 15:10:43 CET 2004 i686 GNU/Linux
The KDE version it uses is 3.1.4 by the way.