Can't enable desktop effects in Fedora 9 Beta (GNOME)

[Scott (angrykeyboarder)]

I'm running Fedora 9 Beta i686.

When I attempt to enable desktop effects (System --> Preferences ---> 
Look & Feel ---> Desktop Effects). The box to enable them pops up, I 
click "Enable Desktop Effects". The screen blanks out and is totally 
white. It then returns after I hit the escape key (it took a bit to 
figure that out) and I'm back to the "enable" box again. 

At that point I just clicked "close".

No desktop effects.

$ sudo /sbin/lspci | grep nVidia
01:00.0 VGA compatible controller: nVidia Corporation NV40 [GeForce 6800 
GT] (rev a1)

That card has 256MB of RAM. I've had no trouble with Compiz recently in 
Betas of Mandriva or Ubuntu.

Is this a bug or a feature? ;)

Any ideas?

Curiously,

	Scott