Did you Google for "overlapped extent allocation"? There's a reasonable amount of hits for it, and most places seem to suggest that DiskWarrior is what you want to fix it.

Also, try booting into OS9 (hard drive or CD) and run its disk repair utility.

You might also try opening a Terminal and running ``sudo find / -inum 242929'' (assuming I'm reading the fsck output correctly) and see what that file is. Delete it if you don't need it. Or try to copy (``cp'') it to another location (check the new file's contents first) and delete it. Then do your fsck maneuver again and see what happens.

Regardless, try that Google search I linked above and read what they have to say.