As many ppl know, some mobs are bugged and they cause a crash server. That's why dire maul is now locked and maybe some other things...
I think that a dev can do something better than just removing the mobs but yeah, that's direct solution. lol
The 2 bugged mobs (murkblood raiders) are in Nagrand at http://fr.wowhead.com/maps?data=3518:313440
Screenshot :
Best regards, Apu.