I managed to get compiz installed last night after posting this message. I then had the problem you described and spent 4 hours pulling my hair wondering what went wrong... So glad you posted how to fix that, thanks alot.
One last thing, my "CUBE" has just the 4 sides, but the top and bottom of the cube is not in use. I'd like those to be desktops also, I actually usually use 6 with xfce or whatever... Is there a setting somewhere to set it from 4 to 6?
Thanks for your help, looking (and working!) great.