I haven't got time right now, but I'll look into this later...
Is this on a new world or one that was recently updated? If updated, has it been more than 15 minutes since you did?
Also if possible could you upload the world so I can reproduce the error, because I did a fair bit of testing before I uploaded the update, and I didn't manage to get it to crash.
Edit: Oh and are you using any other mods?