Yup, it was me. I'll get me coat. Sorry to waste your time, folks. I suddenly realised what the problem must be, and set my mind to hunting for a specific bug, and I soon found it: I was loading the entire world twice. Duh.
Still, I wouldn't have found it so quickly had it not been for this thread, so thanks, guys, for the help. :)
Still, I wouldn't have found it so quickly had it not been for this thread, so thanks, guys, for the help. :)