I upgraded to 2.3 and now my system-prefs behaves strange.
When I call screens, I sometimes get a windown with just "use, save, cancel" but no content !

If I call it again, I get "couldn't use preference class"...

What's going wrong ?

It's been repeated here a gazillion time already: where's the log?

Have you by any chance installed some MUI beta ?

I fixed this today:

muilocale.library is not present, when doing a clean 2.3 install.
You have to copy it from some old installation, than you get the prefs again.