Skeletons let Minecraft crash.

I have this bug in nearly every version of Minecraft. I also redownloaded Minecraft several times but it changed nothing. Everytime I play on a server with my friends Minecraft crashes when the night begins. After a while I understood that this happens when I am in the range of a skeleton or when I can see one. I am sorry for my english but I´m from Germany. I hope you can help me.

Thanks
Miguel