This is only a guess since I am on dialup and havent run apt-get upgrade but I am wondering it that command may have caused your problem by not upgrading some of the pkgs and leaving you broken?

I would try re-installing Knoppix to the hdd agian and just doing apt-get update and then apt-get install whatever.I have installed/remastered Knoppix many many times and never had a problem with apt-get install synaptic (after update) and then using synaptic to install almost anything from the 12,000+ pkgs in my default list.

I do know of some people that have upgraded things like gcc and broke their make tools.