I'm not a Fedora user, but I'd suggest investigating whether or not the DBUS daemon is running, and/or restart kdeinit.
I'm not sure exactly how you would restart the DBUS message daemon on Fedora (a Fedora user will have to help you there, or Google for something like 'fedora howto restart messagebus') but for the kdeinit thing, try these:
Code:
shell# kdeinit4
shell# kdeinit
Try those as root, and as regular user, from a terminal; it may help; but I'm more inclined to believe that the messagebus is the problem.
Sasha