I had the problem with CD/RW and DVD using knx-hdinstall on version 3.2 (9-5-03). My CD/RW is IDE master and worked after install. My DVD drive is IDE slave and did not work. I found that the DVD had the wrong symbolic link. After install, "ls -al /dev/dvd" returned "/dev/dvd -> /KNOPPIX/dev/dvd". I fixed it by:

rm -f /dev/dvd
ln -s /dev/scd1 /dev/dvd

Now I can play movies on Mplayer!