I know that some person had troubles with Mac OS X 10.5. After some investigations, I found the problem. It seems that in get-class-ordered-list, which is responsible to gather all classes, it was entering an infinite loop. The loop was there because it was trying to load a class "Protocol", which has "Protocol" class as Protocol. So, loading "Protocol" class caused to load again "Protocol", which didn't had been registered yet. I just delayed the initialization of :protocols.
The other problem was related to coersing some pointers. However I don't know why it was needed, and it seems to go well without it. There's an another latent problem where I get all those messages:
_NSAutoreleaseNoPool(): Object 0x142c60 of class NSCFArray autoreleased with no pool in place - just leaking
I'm looking into that.
BTW, I'm a newcomer to lisp so, you might want to edit the patch to make it "cleaner"