Mob Arena

2013-02-24 17:54:10 [SEVERE] Error occurred while enabling MobArena v0.94.4.95 (Is it up to date?)
java.lang.IllegalArgumentException: Block must be a sign!
	at com.garbagemule.MobArena.leaderboards.Leaderboard.<init>(Leaderboard.java:64)
	at com.garbagemule.MobArena.ArenaImpl.<init>(ArenaImpl.java:126)
	at com.garbagemule.MobArena.ArenaMasterImpl.loadArena(ArenaMasterImpl.java:559)
	at com.garbagemule.MobArena.ArenaMasterImpl.loadArenasInWorld(ArenaMasterImpl.java:514)
	at com.garbagemule.MobArena.ArenaMasterImpl.loadArenas(ArenaMasterImpl.java:498)
	at com.garbagemule.MobArena.ArenaMasterImpl.initialize(ArenaMasterImpl.java:247)
	at com.garbagemule.MobArena.MobArena.onEnable(MobArena.java:83)
	at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:217)
	at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:457)
	at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:381)
	at org.bukkit.craftbukkit.v1_4_R1.CraftServer.loadPlugin(CraftServer.java:282)
	at org.bukkit.craftbukkit.v1_4_R1.CraftServer.enablePlugins(CraftServer.java:264)
	at net.minecraft.server.v1_4_R1.MinecraftServer.j(MinecraftServer.java:321)
	at net.minecraft.server.v1_4_R1.MinecraftServer.e(MinecraftServer.java:300)
	at net.minecraft.server.v1_4_R1.MinecraftServer.a(MinecraftServer.java:259)
	at net.minecraft.server.v1_4_R1.DedicatedServer.init(DedicatedServer.java:149)
	at net.minecraft.server.v1_4_R1.MinecraftServer.run(MinecraftServer.java:399)
	at net.minecraft.server.v1_4_R1.ThreadServerApplication.run(SourceFile:849)