This website and wiki for Compiz should help.
Also it could be in your Compiz Fusion Settings (the way you have things set)might be why it's not working in the Gnome Desktop environment.
When I used Compiz with Ubuntu I had to go into Compiz Fusion Manager and do a little adjusting a few times to get it to work properly.
Here is the whole search for compiz and Linux Mint:
Hope this helps.