Gettings some wierd client crash. The crash happends on world load.

Here is the crash log: http://pastebin.com/GmmhGkrT

Seems to be completly random.

Strange - I have no clue how this could happen, nor how I could fix it. Does it happen every time you load the world?

java.lang.IndexOutOfBoundsException: Index: 22, Size: 23
I think that java is drunk.

Ah yes, the issue here is that you've unfortunately proven that 22 ≥ 23, which indicates a deeper issue with the very axioms upon which mathematics is constructed. I'm not sure how to fix arithmetic collapse; it's a bit beyond my remit as a modder.

Seriously though, this is an odd crash - it's caused by something internal to Minecraft as far as I can tell, and there's probably not much we can do to fix it.

Sorry :(