OpenSUSE :: Getting Black Background With KDE4?

I've been running KDE4 with Suse 11.2 for about a year or so now, with no problems. Yesterday, the background to my screen suddenly went black. Open windows were unaffected, but I could see my theme, the task manager, etc. I couldn't open any programs other than the ones already open (and ones that they launch).This problem was system-wide, in that it affects all accounts on my machine.I thought I'd solved the problem after discussion with someone by email, by forcing KDE to recreate itself. I did this by

mv ~/.kde4 ~/oldkde4

then relogging. This, in itself, seemed to make matters worse, so I went

mv ~/.kde4 ~/newkde4
mv ~/oldkde4 ~/.kde4

and relogged. To my surprise, everything worked thereafter for a few hours.

I think this was coincidence, because, after a few hours, the same thing happened and the "fix" didn't work anymore.I checked .xsession-error and it says

/etc/X11/xim: Checking whether an input method should be started.
sourcing /etc/sysconfig/language to get the value of INPUT_METHOD
INPUT_METHOD is not set or empty (no user selected input method).

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