Not a direct answer to your problem, because I don't know the answer. But I'd like to mention the following:
LXDE is meant for being lightweight and agile. Compiz is far from that. It's a resource hog. Installing Compiz in LXDE, more or less defeats the purpose of LXDE.... Using Compiz in LXDE is like pulling a caravan with a Suzuki Alto.
So I'd advise you to reconsider Compiz in LXDE. Compiz is fine in a big fat desktop environment like Gnome, that's it's natural habitat.