Minecraft Crashes after recent update

Minecraft crashes when loading world

What I expected to happen was...:
Game should have loaded world.

What actually happened was...:
After upgrading MC to version 1.5.1 when starting to load a world, program stops with a backround in place then crashes and gives an error report.

Steps to Reproduce:
1. Start program
2. Log into environment
3. Select world
4. Programs fails to load world and give an error report (attached)