Version-Release number of selected component (if applicable):
compiz-0.0.13-0.23.20060817git.fc6

How reproducible:
100% on this machine

Steps to Reproduce:
1. run from the panel (Desktop->Preferences->More Preferences->Desktop Effects) 
2. click on Enable Desktop Effects button

  
Actual results:
Chaos on screen for about 10 seconds, after which the display is restored, with
the button sensitized.  A few seconds later, chaos begins again, some seconds
later the button is back to how it was before.

There's no visible output that an error occurred.

If I run desktop-effects from a terminal, the following is logged to the terminal:
GTK Accessibility Module initialized
string: metacity
attempting to run compiz
GTK Accessibility Module initialized
gnome-window-decorator: Screen 0 on display ":0.0" already has a decoration
manager; try using the --replace option to replace the current decoration manager.
compiz: No GLXFBConfig for default depth, this isn't going to work.
compiz: Failed to manage screen: 0
compiz: No managable screens found on display :0.0
GTK Accessibility Module initialized

Expected results:
Would hope that an error dialog of some kind would have popped up saying that it
didn't work, possibly containing the textual output from above, or at least
recommending that I run things from a terminal to gather further information.