[18:09:52 WARN]: Unexpected exception while parsing console command "visibility"

org.bukkit.command.CommandException: Unhandled exception executing command 'visi
bility' in plugin Visibility v1.2
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[spi
got-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:18
1) ~[spigot-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
        at org.bukkit.craftbukkit.v1_7_R4.CraftServer.dispatchCommand(CraftServe
r.java:767) ~[spigot-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
        at org.bukkit.craftbukkit.v1_7_R4.CraftServer.dispatchServerCommand(Craf
tServer.java:753) [spigot-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
        at net.minecraft.server.v1_7_R4.DedicatedServer.aB(DedicatedServer.java:
326) [spigot-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
        at net.minecraft.server.v1_7_R4.DedicatedServer.v(DedicatedServer.java:2
90) [spigot-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
        at net.minecraft.server.v1_7_R4.MinecraftServer.u(MinecraftServer.java:5
84) [spigot-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
        at net.minecraft.server.v1_7_R4.MinecraftServer.run(MinecraftServer.java
:490) [spigot-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
        at net.minecraft.server.v1_7_R4.ThreadServerApplication.run(SourceFile:6
28) [spigot-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
Caused by: java.lang.ClassCastException: org.bukkit.craftbukkit.v1_7_R4.command.
ColouredConsoleSender cannot be cast to org.bukkit.entity.Player
        at me.Mali_Plavi.visibility.Main.onCommand(Main.java:40) ~[?:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[spi
got-20141113a.jar:git-Spigot-1.7.9-R0.2-208-ge0f2e95]
        ... 8 more