Random worlds wont load on CB 1.0 pre-release

So I've experienced this a couple times, and from what others have said, it appears to be a bukkit bug.
Im running Multiverse and have 6 worlds. Today after updating, it would stop on preparing world 4 etc, after removing that world from the config, it would then load fine.

Trying to import that world, it does the same thing. I tried runing chunkster on it, with no positive effect at fixing the problem. I was able to load it in MCEdit, and single player just fine.

Does anyone have any ideas whats causing this or how to fix it?