Originally posted by makuyl
Well, that's probably it. The needed files for X, kdm and kde can't be written to /tmp as there's no space. Delete some log files under /var/log or run logrotate, and remove some unneeded packages with kpackage or apt. There are lots of packages in knoppix which you probably have no need for.
Okay, that fixed everything. I appreciate all the help, and thanks!