01:00:42 [SEVERE] Could not pass event PlayerCommandPreprocessEvent to cIP v0.5.9
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:427)
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
        at org.bukkit.plugin.TimedRegisteredListener.callEvent(TimedRegisteredListener.java:26)
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:479)
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:464)
        at net.minecraft.server.v1_5_R2.PlayerConnection.handleCommand(PlayerConnection.java:971)
        at net.minecraft.server.v1_5_R2.PlayerConnection.chat(PlayerConnection.java:896)
        at net.minecraft.server.v1_5_R2.PlayerConnection.a(PlayerConnection.java:841)
        at net.minecraft.server.v1_5_R2.Packet3Chat.handle(Packet3Chat.java:44)
        at org.spigotmc.netty.NettyNetworkManager.b(NettyNetworkManager.java:176)
        at net.minecraft.server.v1_5_R2.PlayerConnection.d(PlayerConnection.java:110)
        at net.minecraft.server.v1_5_R2.ServerConnection.b(SourceFile:35)
        at org.spigotmc.netty.NettyServerConnection.b(NettyServerConnection.java:66)
        at net.minecraft.server.v1_5_R2.MinecraftServer.r(MinecraftServer.java:580)
        at net.minecraft.server.v1_5_R2.DedicatedServer.r(DedicatedServer.java:229)
        at net.minecraft.server.v1_5_R2.MinecraftServer.q(MinecraftServer.java:469)
        at net.minecraft.server.v1_5_R2.MinecraftServer.run(MinecraftServer.java:401)
        at net.minecraft.server.v1_5_R2.ThreadServerApplication.run(SourceFile:573)
Caused by: java.lang.IllegalArgumentException: Command cannot be empty
        at org.apache.commons.lang.Validate.notEmpty(Validate.java:363)
        at org.bukkit.event.player.PlayerCommandPreprocessEvent.setMessage(PlayerCommandPreprocessEvent.java:62)
        at me.PS.cIP.cIP.onPlayerCommandPreprocess(cIP.java:518)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        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:425)
        ... 17 more