pvparena_errors on server stop

2013-12-27 06:19:44 [INFO] [PVP Arena] Disabling pvparena v1.1.0.317
2013-12-27 06:19:44 [SEVERE] Error occurred while disabling pvparena v1.1.0.317 (Is it up to date?)
java.lang.NoClassDefFoundError: net/slipcor/pvparena/loadables/ArenaRegionShape$RegionType
	at net.slipcor.pvparena.modules.blockrestore.Blocks.restoreChests(Blocks.java:241)
	at net.slipcor.pvparena.modules.blockrestore.Blocks.reset(Blocks.java:211)
	at net.slipcor.pvparena.loadables.ArenaModuleManager.reset(ArenaModuleManager.java:249)
	at net.slipcor.pvparena.arena.Arena.reset(Arena.java:1134)
	at net.slipcor.pvparena.managers.ArenaManager.reset(ArenaManager.java:344)
	at net.slipcor.pvparena.PVPArena.onDisable(PVPArena.java:303)
	at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:219)
	at org.bukkit.plugin.java.JavaPluginLoader.disablePlugin(JavaPluginLoader.java:481)
	at org.bukkit.plugin.SimplePluginManager.disablePlugin(SimplePluginManager.java:400)
	at org.bukkit.plugin.SimplePluginManager.disablePlugins(SimplePluginManager.java:393)
	at org.bukkit.craftbukkit.v1_6_R3.CraftServer.disablePlugins(CraftServer.java:279)
	at net.minecraft.server.v1_6_R3.MinecraftServer.stop(MinecraftServer.java:345)
	at net.minecraft.server.v1_6_R3.MinecraftServer.run(MinecraftServer.java:452)
	at net.minecraft.server.v1_6_R3.ThreadServerApplication.run(SourceFile:583)
Caused by: java.lang.ClassNotFoundException: net.slipcor.pvparena.loadables.ArenaRegionShape$RegionType
	at java.net.URLClassLoader$1.run(Unknown Source)
	at java.net.URLClassLoader$1.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at java.net.FactoryURLClassLoader.loadClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	... 14 more