The game crashes whenever i go near a mobspawner.

Put the summary of the bug you're having here

What I expected to happen was...:
that i could go in to my building / cit

What actually happened was...: I go near the spawner and the hole game closes. even if i'm 10 blocks away.

Steps to Reproduce:
1. Go near a spavwer
2. the game crashes
3. trow your PC in the ground an yell f***.