Why did my minecraft crash? (Crash Report Below)?

Description: Ticking entity
java.lang.ArrayIndexOutOfBoundsExceptio… 506
at net.minecraft.entity.monster.EntityEnder…
at net.minecraft.entity.EntityLivingBase.fu…
at net.minecraft.entity.EntityLiving.func_7…
at net.minecraft.entity.monster.EntityMob.f…
at net.minecraft.world.World.func_72866_a(W…
at net.minecraft.world.WorldServer.func_728…
at net.minecraft.world.World.func_72870_g(W…
at net.minecraft.world.World.func_72939_s(W…
at net.minecraft.world.WorldServer.func_729…
at net.minecraft.server.MinecraftServer.fun…
at net.minecraft.server.MinecraftServer.fun…
at net.minecraft.server.integrated.Integrat…
at net.minecraft.server.MinecraftServer.run…
at net.minecraft.server.MinecraftServer$2.r…

Please email me for the full crash report at stephenminor@rocketmail.com. I do have a few mods installed such as bibliocraft lotofmobs abyssalcraft and NEI.

Guest

Because your computer probably couldn't handle it

Jordan