1.6.2 Compatibilty (WIP - Please do not pull)

I'm partially opening this just so you know I'm working on this, and to keep some sort of communication open trying to fix whatever issue is causing this: http://hopper.minecraft.net/help/error-chatting-server/

The client error trace is here: https://gist.github.com/zifnab06/6076652

I'll keep debugging and try to figure out what is actually causing this tonight.