15:01:41 [SEVERE] java.lang.InstantiationException
15:01:41 [SEVERE]       at sun.reflect.InstantiationExceptionConstructorAccessorImpl.newInstance(InstantiationExceptionConstructorAccessorImpl.java:30)
15:01:41 [SEVERE]       at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
15:01:41 [SEVERE]       at net.minecraft.server.EntityTypes.a(SourceFile:67)
15:01:41 [SEVERE]       at net.minecraft.server.TileEntityMobSpawner.h_(TileEntityMobSpawner.java:51)
15:01:41 [SEVERE]       at net.minecraft.server.World.cleanUp(World.java:1112)
15:01:41 [SEVERE]       at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:460)
15:01:41 [SEVERE]       at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:374)
15:01:41 [SEVERE]       at net.minecraft.server.ThreadServerApplication.run(SourceFile:417)