[SEVERE] Could not pass event PlayerInteractEvent to MachineGuardReloaded v1.3
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:437)
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
        at org.bukkit.plugin.TimedRegisteredListener.callEvent(TimedRegisteredListener.java:31)
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:479)
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:464)
        at org.bukkit.craftbukkit.v1_6_R3.event.CraftEventFactory.callPlayerInteractEvent(CraftEventFactory.java:193)
        at net.minecraft.item.ItemInWorldManager.func_73074_a(ItemInWorldManager.java:173)
        at net.minecraft.network.NetServerHandler.func_72510_a(NetServerHandler.java:771)
        at net.minecraft.network.packet.Packet14BlockDig.func_73279_a(Packet14BlockDig.java:67)
        at net.minecraft.network.TcpConnection.func_74428_b(TcpConnection.java:470)
        at net.minecraft.network.NetServerHandler.func_72570_d(NetServerHandler.java:233)
        at net.minecraft.network.NetworkListenThread.func_71747_b(NetworkListenThread.java:54)
        at net.minecraft.server.dedicated.DedicatedServerListenThread.func_71747_b(DedicatedServerListenThread.java:34)
        at net.minecraft.server.MinecraftServer.func_71190_q(MinecraftServer.java:914)
        at net.minecraft.server.dedicated.DedicatedServer.func_71190_q(DedicatedServer.java:330)
        at net.minecraft.server.MinecraftServer.func_71217_p(MinecraftServer.java:781)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:663)
        at net.minecraft.server.ThreadMinecraftServer.run(ThreadMinecraftServer.java:16)
Caused by: java.lang.NoClassDefFoundError: com/sk89q/worldguard/bukkit/WorldGuardPlugin
        at ru.onlymc.MachineGuardReloaded.MGListener.onPlayerInteract(MGListener.java:51)
        at sun.reflect.GeneratedMethodAccessor26.invoke(Unknown Source)
        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:435)
        ... 17 more