/dxl invite bug

[Sataniel98]

[13:22:31 ERROR]: null
org.bukkit.command.CommandException: Unhandled exception executing command 'dxl' in plugin DungeonsXL v0.15.2
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46) ~[spigot-1.11.jar:git-Spigot-f950f8e-eb6c1bf]
        at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) ~[spigot-1.11.jar:git-Spigot-f950f8e-eb6c1bf]
        at org.bukkit.craftbukkit.v1_11_R1.CraftServer.dispatchCommand(CraftServer.java:649) ~[spigot-1.11.jar:git-Spigot-f950f8e-eb6c1bf]
        at net.minecraft.server.v1_11_R1.PlayerConnection.handleCommand(PlayerConnection.java:1335) [spigot-1.11.jar:git-Spigot-f950f8e-eb6c1bf]
        at net.minecraft.server.v1_11_R1.PlayerConnection.a(PlayerConnection.java:1170) [spigot-1.11.jar:git-Spigot-f950f8e-eb6c1bf]
        at net.minecraft.server.v1_11_R1.PacketPlayInChat.a(PacketPlayInChat.java:45) [spigot-1.11.jar:git-Spigot-f950f8e-eb6c1bf]
        at net.minecraft.server.v1_11_R1.PacketPlayInChat.a(PacketPlayInChat.java:1) [spigot-1.11.jar:git-Spigot-f950f8e-eb6c1bf]
        at net.minecraft.server.v1_11_R1.PlayerConnectionUtils$1.run(SourceFile:13) [spigot-1.11.jar:git-Spigot-f950f8e-eb6c1bf]
        at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source) [?:1.8.0_74]
        at java.util.concurrent.FutureTask.run(Unknown Source) [?:1.8.0_74]
        at net.minecraft.server.v1_11_R1.SystemUtils.a(SourceFile:46) [spigot-1.11.jar:git-Spigot-f950f8e-eb6c1bf]
        at net.minecraft.server.v1_11_R1.MinecraftServer.D(MinecraftServer.java:739) [spigot-1.11.jar:git-Spigot-f950f8e-eb6c1bf]
        at net.minecraft.server.v1_11_R1.DedicatedServer.D(DedicatedServer.java:399) [spigot-1.11.jar:git-Spigot-f950f8e-eb6c1bf]
        at net.minecraft.server.v1_11_R1.MinecraftServer.C(MinecraftServer.java:675) [spigot-1.11.jar:git-Spigot-f950f8e-eb6c1bf]
        at net.minecraft.server.v1_11_R1.MinecraftServer.run(MinecraftServer.java:574) [spigot-1.11.jar:git-Spigot-f950f8e-eb6c1bf]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_74]
Caused by: java.lang.NullPointerException
        at io.github.dre2n.dungeonsxl.config.WorldConfig.save(WorldConfig.java:305) ~[?:?]
        at io.github.dre2n.dungeonsxl.world.DResourceWorld.addInvitedPlayer(DResourceWorld.java:148) ~[?:?]
        at io.github.dre2n.dungeonsxl.command.InviteCommand.onExecute(InviteCommand.java:53) ~[?:?]
        at io.github.dre2n.dungeonsxl.util.commons.command.BRCommandExecutor.onCommand(BRCommandExecutor.java:71) ~[?:?]
        at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44) ~[spigot-1.11.jar:git-Spigot-f950f8e-eb6c1bf]
        ... 15 more