Just updated to 10.5.4, and still having drops outs in the keyboard shortcuts. Spotlight, Expose, Spaces and the mouse allocations for those don't work either. I can't seem to find any info relating to this - i did a little while ago, and the culprit was the Last FM plug-in (which is now removed) - but still no joy. Can anyone shed some light on this? Hugely frustrating as i really need to Spaces and Spotlight to work...

Muchas Gracias!

Try reinstalling the latest combo updater?

Okay did all that, and that didn't resolve anything.

But, found this out today - It's Polarclock 3 screensaver used on a dual screen setup that will trigger the problem. Setting the screensaver to appear on main screen only fixes the problem. In the meantime Pixelbreaker has reported the bug in code to screentime...