Comment 7 for bug 56051

Had to cope with the same problem after updating KDE from 3.5.3 (?) to 3.5.5. Clicking on Appearance in systemsettings made the whole application crash wth a similar backtrace. I noticed that the kbfx entry in kcotnrol crashed too. I managed to solve the issue with systemsettings by deinstalling kbfx (and a related themes package) and now i can activate the Appearance icon again.