MC-HG Error

14:32:44 [SEVERE] Could not pass event PlayerMoveEvent to MCHungerGames
java.lang.NullPointerException
        at org.bukkit.craftbukkit.CraftServer.getWorld(CraftServer.java:921)
        at org.bukkit.Bukkit.getWorld(Bukkit.java:166)
        at com.acuddlyheadcrab.MCHungerGames.Arenas.getCenter(Arenas.java:49)
        at com.acuddlyheadcrab.MCHungerGames.Arenas.isWithinArena(Arenas.java:268)
        at com.acuddlyheadcrab.MCHungerGames.Arenas.getNearbyArena(Arenas.java:274)
        at com.acuddlyheadcrab.MCHungerGames.TributeListener.onPlayerMove(TributeListener.java:158)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:601)
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:301)
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:461)
        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:209)
        at net.minecraft.server.Packet10Flying.handle(SourceFile:126)
        at net.minecraft.server.NetworkManager.b(NetworkManager.java:229)
        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:113)
        at org.getspout.spout.SpoutNetServerHandler.a(SpoutNetServerHandler.java:169)
        at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:92)
        at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:622)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:506)
        at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
14:32:44 [SEVERE] Could not pass event PlayerTeleportEvent to MCHungerGames
java.lang.NullPointerException
        at org.bukkit.craftbukkit.CraftServer.getWorld(CraftServer.java:921)
        at org.bukkit.Bukkit.getWorld(Bukkit.java:166)
        at com.acuddlyheadcrab.MCHungerGames.Arenas.getCenter(Arenas.java:49)
        at com.acuddlyheadcrab.MCHungerGames.Arenas.isWithinArena(Arenas.java:268)
        at com.acuddlyheadcrab.MCHungerGames.Arenas.getNearbyArena(Arenas.java:274)
        at com.acuddlyheadcrab.MCHungerGames.TributeListener.onPlayerTP(TributeListener.java:109)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:601)
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:301)
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:461)
        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:425)
        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:392)
        at net.minecraft.server.Packet10Flying.handle(SourceFile:126)
        at net.minecraft.server.NetworkManager.b(NetworkManager.java:229)
        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:113)
        at org.getspout.spout.SpoutNetServerHandler.a(SpoutNetServerHandler.java:169)
        at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:92)
        at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:622)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:506)
        at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)