2011-02-17 19:23:29 [SEVERE] Unexpected exception
java.lang.ArrayIndexOutOfBoundsException: -1
        at net.minecraft.server.ChunkCache.getTypeId(SourceFile:38)
        at net.minecraft.server.ChunkCache.getMaterial(SourceFile:103)
        at net.minecraft.server.Pathfinder.a(SourceFile:158)
        at net.minecraft.server.Pathfinder.a(SourceFile:120)
        at net.minecraft.server.Pathfinder.b(SourceFile:94)
        at net.minecraft.server.Pathfinder.a(SourceFile:64)
        at net.minecraft.server.Pathfinder.a(SourceFile:37)
        at net.minecraft.server.Pathfinder.a(SourceFile:22)
        at net.minecraft.server.World.a(World.java:1678)
        at net.minecraft.server.EntityCreature.d(EntityCreature.java:69)
        at net.minecraft.server.EntityLiving.o(EntityLiving.java:641)
        at net.minecraft.server.EntityMonster.o(EntityMonster.java:30)
        at net.minecraft.server.EntitySkeleton.o(EntitySkeleton.java:54)
        at net.minecraft.server.EntityLiving.b_(EntityLiving.java:226)
        at net.minecraft.server.EntityMonster.b_(EntityMonster.java:34)
        at net.minecraft.server.Entity.D(Entity.java:931)
        at net.minecraft.server.EntityLiving.D(EntityLiving.java:219)
        at net.minecraft.server.World.a(World.java:1057)
        at net.minecraft.server.WorldServer.a(WorldServer.java:55)
        at net.minecraft.server.World.f(World.java:1041)
        at net.minecraft.server.World.a(World.java:1102)
        at net.minecraft.server.WorldServer.a(WorldServer.java:55)
        at net.minecraft.server.World.f(World.java:1041)
        at net.minecraft.server.World.c(World.java:1018)
        at net.minecraft.server.MinecraftServer.h(MinecraftServer.java:313)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:232)
        at net.minecraft.server.ThreadServerApplication.run(SourceFile:512)