Why are you trying to OOify obj_to_room?  Given its destructive nature (see above), it does not lend itself well to object oriented programming;  somewhere youve probably got some loop which is getting screwed up by invalid pointers due to a clumsy use of this very clumsy OOP.

...
Actually, why are you making SMAUG OO at all?  It is utterly pointless and a massive waste of time.

EDIT:  Oops, sorry, I meant to say "AFKMud", not "SMAUG" :P   (read:  SMAUG with a couple pages worth of buggy snippets added)