Minecraft Broke.

It Won't work when I play.. the error report is attached...

What I expected to happen was...:
It would play the world when I double clicked it.

What actually happened was...:
It said generating world... for about 20 seconds then it gave an error report

Steps to Reproduce:
1.I started Minecraft
2.played a world
3.and it gave an error report.. PLESE HELP ME!!!!