2013-03-23 06:36:37 [INFO] [mcore] Enabling mcore v6.1.0
2013-03-23 06:36:37 [INFO] [mcore 6.1.0] === ENABLE START ===
2013-03-23 06:36:37 [SEVERE] Error occurred while enabling mcore v6.1.0 (Is it up to date?)
java.lang.NoClassDefFoundError: net/minecraft/server/v1_5_R1/Packet
	at com.massivecraft.mcore.MCore.onEnable(MCore.java:114)
	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:383)
	at org.bukkit.craftbukkit.v1_5_R2.CraftServer.loadPlugin(CraftServer.java:304)
	at org.bukkit.craftbukkit.v1_5_R2.CraftServer.enablePlugins(CraftServer.java:286)
	at org.bukkit.craftbukkit.v1_5_R2.CraftServer.<init>(CraftServer.java:240)
	at net.minecraft.server.v1_5_R2.PlayerList.<init>(PlayerList.java:56)
	at net.minecraft.server.v1_5_R2.DedicatedPlayerList.<init>(SourceFile:11)
	at net.minecraft.server.v1_5_R2.DedicatedServer.init(DedicatedServer.java:109)
	at net.minecraft.server.v1_5_R2.MinecraftServer.run(MinecraftServer.java:387)
	at net.minecraft.server.v1_5_R2.ThreadServerApplication.run(SourceFile:573)
Caused by: java.lang.ClassNotFoundException: net.minecraft.server.v1_5_R1.Packet
	at org.bukkit.plugin.java.PluginClassLoader.findClass0(PluginClassLoader.java:70)
	at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:53)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:423)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:356)
	... 12 more