I got a bug in MC Forge...
If i start to dig a block (no matter what sort of block) in MC it crashes instantly.
No mods/resourcepacks are installed.... Except for Forge.
fml-client-latest:
http://pastebin.com/5XLEDEG4
Minecraft Crash Report:
http://pastebin.com/pk6XwyjP
//edit
Version 12.16.0.1767 fixed the Problem.