i go on mcwithercraft.org and my game crashes but it only happens on that server

Put the summary of the bug you're having here

What I expected to happen was...: go on the server and start where i was
Describe what you thought should happen here

*What actually happened was...:*i crashed
Describe what happened here

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...
3. ...