SCS Error

16:00:20 [INFO] Cool_Designer issued server command: /scs display this
16:00:20 [SEVERE] null
org.bukkit.command.CommandException: Unhandled exception executing command 'scs' in plugin ShowCaseStandalone v383
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46)
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:189)
        at org.bukkit.craftbukkit.v1_6_R2.CraftServer.dispatchCommand(CraftServer.java:523)
        at net.minecraft.server.v1_6_R2.PlayerConnection.handleCommand(PlayerConnection.java:962)
        at net.minecraft.server.v1_6_R2.PlayerConnection.chat(PlayerConnection.java:880)
        at net.minecraft.server.v1_6_R2.PlayerConnection.a(PlayerConnection.java:837)
        at net.minecraft.server.v1_6_R2.Packet3Chat.handle(SourceFile:49)
        at net.minecraft.server.v1_6_R2.NetworkManager.b(NetworkManager.java:296)
        at net.minecraft.server.v1_6_R2.PlayerConnection.e(PlayerConnection.java:116)
        at net.minecraft.server.v1_6_R2.ServerConnection.b(SourceFile:37)
        at net.minecraft.server.v1_6_R2.DedicatedServerConnection.b(SourceFile:30)
        at net.minecraft.server.v1_6_R2.MinecraftServer.t(MinecraftServer.java:590)
        at net.minecraft.server.v1_6_R2.DedicatedServer.t(DedicatedServer.java:226)
        at net.minecraft.server.v1_6_R2.MinecraftServer.s(MinecraftServer.java:486)
        at net.minecraft.server.v1_6_R2.MinecraftServer.run(MinecraftServer.java:419)
        at net.minecraft.server.v1_6_R2.ThreadServerApplication.run(SourceFile:582)
Caused by: java.lang.NoClassDefFoundError: net/minecraft/server/v1_4_6/NBTBase
        at com.kellerkindt.scs.commands.DisplayCmd.execute(DisplayCmd.java:88)
        at com.kellerkindt.scs.listeners.CommandExecutorListener.onCommand(CommandExecutorListener.java:157)
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)
        ... 15 more
Caused by: java.lang.ClassNotFoundException: net.minecraft.server.v1_4_6.NBTBase
        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(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        ... 18 more