What he said.

What I mean is, if you want Debian Unstable, install Debian Unstable (actually, you don't install Debian Unstable, you install Debian Testing and dist-upgrade to Unstable -- broadband helps!). That way, you have a clean install. If you want to stick with your Knoppix variant, you'll have to accept that there are some things you can't upgrade without "breaking the plumbing."