Is KDE the only window manager that doesn't work? I'm sure that KDM should have some other WM's you can try just to see if you can actually login. I'm thinking that if you have upgraded KDE then KDM *may* not be pointing to the correct location for KDE 3.3.
It's just a thought, I've never tried to upgrade whole window managers from RPM's since the last time I tried to, and failed.
Also, you may want to try pressing CTRL-ALT-F1 altogether to get to a terminal login screen, logging in, and then try loading kde manually by typing
If you really want a fresh clean install of KDE though your best bet, IMO, is to try installing MDK10.1CE from scratch rather than upgrading. I stil don't believe the process works well enough and often enough to upgrade. Somebody prove me wrong though!