Re: compiz not working here
This has nothing to do with your graphics card. Please read the error messages you posted:
/usr/bin/compiz.real (core) - Error: Another window manager is already running on screen: 0
/usr/bin/compiz.real (core) - Fatal: No manageable screens found on display :0
No other errors are mentioned. No mention of graphics card or driver problems. It sounds like the only real problem you have is a compiz configuration one. If you're using modern builds of compiz, beryl-manager probably won't work right.