Hi! There is a crash with the server when I am just flying and wandering around the map and maybe when I look at a mob with a hat or a mob with a hat spawned, Minecraft crashed. Here is the error log:

http://pastebin.com/auPBhSd1

Would be more than welcome if there is a solution to this!

What does that crash have to do with this mod? Its says its caused by mystcraft ...