Well, the other thing I'd try, then, is resetting the KDE configuration information, by deleting ~/.kde. That can work wonders. Of course, you probably don't want to lose all of that, so log out of KDE, open up a virtual terminal (Alt+Ctrl+1 or some such thing should do it), log in as yourself, and move that directory somewhere else, e.g.:
#mv ~/.kde ~/oldkde
Then go back to xdm or whatever (Alt+Ctrl+7, probably) and log back into KDE. If that doesn't fix the problem, you can go through the process again and move your old configuration back into place. If it does, you can copy over parts of the configuation (say, your amarok settings, from ~oldkde/share/config/amarokrc) that were unlikely to be causing problems.
The other thing you might do is check to make sure none of the KDE files themselves got corrupted somehow. You can use "rpm -V" to compare checksums on the installed files to those held in the rpm database.