[11:35:27 ERROR]: Could not pass event InventoryClickEvent to TrainingPvP v2.0.2
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:302) ~[minecraft_server.jar:git-Spigot-1649]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[minecraft_server.jar:git-Spigot-1649]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:514) [minecraft_server.jar:git-Spigot-1649]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:499) [minecraft_server.jar:git-Spigot-1649]
        at net.minecraft.server.v1_7_R4.PlayerConnection.a(PlayerConnection.java:1477) [minecraft_server.jar:git-Spigot-1649]
        at net.minecraft.server.v1_7_R4.PacketPlayInWindowClick.a(PacketPlayInWindowClick.java:15) [minecraft_server.jar:git-Spigot-1649]
        at net.minecraft.server.v1_7_R4.PacketPlayInWindowClick.handle(PacketPlayInWindowClick.java:65) [minecraft_server.jar:git-Spigot-1649]
        at net.minecraft.server.v1_7_R4.NetworkManager.a(NetworkManager.java:186) [minecraft_server.jar:git-Spigot-1649]
        at net.minecraft.server.v1_7_R4.ServerConnection.c(ServerConnection.java:81) [minecraft_server.jar:git-Spigot-1649]
        at net.minecraft.server.v1_7_R4.MinecraftServer.v(MinecraftServer.java:734) [minecraft_server.jar:git-Spigot-1649]
        at net.minecraft.server.v1_7_R4.DedicatedServer.v(DedicatedServer.java:289) [minecraft_server.jar:git-Spigot-1649]
        at net.minecraft.server.v1_7_R4.MinecraftServer.u(MinecraftServer.java:584) [minecraft_server.jar:git-Spigot-1649]
        at net.minecraft.server.v1_7_R4.MinecraftServer.run(MinecraftServer.java:490) [minecraft_server.jar:git-Spigot-1649]
        at net.minecraft.server.v1_7_R4.ThreadServerApplication.run(SourceFile:628) [minecraft_server.jar:git-Spigot-1649]
Caused by: org.kitteh.tag.api.TagAPIException: Can't submit offline player!
        at org.kitteh.tag.TagAPI.refreshPlayer(TagAPI.java:124) ~[?:?]
        at me.jeroenhero123.TrainingPvP.Objects.Arena.start(Arena.java:466) ~[?:?]
        at me.jeroenhero123.TrainingPvP.Inventories.KitGUI.onClick(KitGUI.java:133) ~[?:?]
        at sun.reflect.GeneratedMethodAccessor415.invoke(Unknown Source) ~[?:?]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_45]
        at java.lang.reflect.Method.invoke(Method.java:497) ~[?:1.8.0_45]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:298) ~[minecraft_server.jar:git-Spigot-1649]
        ... 13 more