@Omid Mottaghi:
Your issue is different, and I'd guess you have Metacity's compositor enabled. My understanding is that Metacity fails to properly release it's hold on Composite when being replaced; thus, Compiz can't gain the composite manager selection, and cannot continue.
Simply disabling Metacity's composite manager should allow you to get Compiz working (or, at least, allow you to hit real bugs in Compiz/mesa/X :))
@Omid Mottaghi:
Your issue is different, and I'd guess you have Metacity's compositor enabled. My understanding is that Metacity fails to properly release it's hold on Composite when being replaced; thus, Compiz can't gain the composite manager selection, and cannot continue.
Simply disabling Metacity's composite manager should allow you to get Compiz working (or, at least, allow you to hit real bugs in Compiz/mesa/X :))