Isn't the Darfur conflict mainly about Sudanese Arab Muslims in and connected to the government attacking Sudanese non-Arab Muslims who are not part of the Sudanese Government? Who are the "Crusaders"?
UBL is likely (1) complaining that all the kaffir in Dafur haven't been put to the sword yet because of crusader-like interferences or (2) looking for a new homebase in N. Sudan and this is his howdy to the Muslim tyrants there or (3) setting a false lead -- he's headed eastward so he points our effort westwards. Three is cool because if we bite (which we should for the sake of stopping the genocide) it may also settle some scores he may have with those big mulsim muck-a-mucks in the Sudan who once tried to turn him over to Clinton.