When I log onto "mc.fearpvp.com" as soon as the world is loaded as well as chat my minecraft crashes

Put the summary of the bug you're having here

What I expected to happen was...:
I expected the world to load properly so I could play on the server

What actually happened was...:
The game crashed

Steps to Reproduce:
1. Launch minecraft
2. ... log onto the server
3. ... wait for the world to load.. then next thing you know it crashes