Live Chat --Bukkit-- Problems

19:39:31 [INFO] Loaded player file for commando323
19:39:31 [SEVERE] Could not pass event PlayerJoinEvent to LiveChat v3.7
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:427)
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.jav
a:62)
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.j
ava:477)
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.j
ava:462)
        at net.minecraft.server.v1_6_R2.PlayerList.c(PlayerList.java:207)
        at net.minecraft.server.v1_6_R2.PlayerList.a(PlayerList.java:103)
        at net.minecraft.server.v1_6_R2.PendingConnection.e(PendingConnection.ja
va:133)
        at net.minecraft.server.v1_6_R2.PendingConnection.d(PendingConnection.ja
va:43)
        at net.minecraft.server.v1_6_R2.DedicatedServerConnectionThread.a(Dedica
tedServerConnectionThread.java:41)
        at net.minecraft.server.v1_6_R2.DedicatedServerConnection.b(SourceFile:2
9)
        at net.minecraft.server.v1_6_R2.MinecraftServer.t(MinecraftServer.java:5
90)
        at net.minecraft.server.v1_6_R2.DedicatedServer.t(DedicatedServer.java:2
26)
        at net.minecraft.server.v1_6_R2.MinecraftServer.s(MinecraftServer.java:4
86)
        at net.minecraft.server.v1_6_R2.MinecraftServer.run(MinecraftServer.java
:419)
        at net.minecraft.server.v1_6_R2.ThreadServerApplication.run(SourceFile:5
82)
Caused by: java.lang.NullPointerException
        at net.milkbowl.vault.chat.plugins.Chat_GroupManager.getPrimaryGroup(Cha
t_GroupManager.java:329)
        at net.milkbowl.vault.chat.Chat.getPrimaryGroup(Chat.java:732)
        at me.main.LiveChat.PlayerDisplayName.main(PlayerDisplayName.java:18)
        at me.main.LiveChat.Listeners.JoinListener.onPlayerJoin(JoinListener.jav
a:21)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:425)
        ... 14 more
19:39:35 [SEVERE] Could not pass event PlayerCommandPreprocessEvent to LiveChat
v3.7
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:427)
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.jav
a:62)
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.j
ava:477)
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.j
ava:462)
        at net.minecraft.server.v1_6_R2.PlayerConnection.handleCommand(PlayerCon
nection.java:946)
        at net.minecraft.server.v1_6_R2.PlayerConnection.chat(PlayerConnection.j
ava:872)
        at net.minecraft.server.v1_6_R2.PlayerConnection.a(PlayerConnection.java
:829)
        at net.minecraft.server.v1_6_R2.Packet3Chat.handle(SourceFile:49)
        at net.minecraft.server.v1_6_R2.NetworkManager.b(NetworkManager.java:296
)
        at net.minecraft.server.v1_6_R2.PlayerConnection.e(PlayerConnection.java
:116)
        at net.minecraft.server.v1_6_R2.ServerConnection.b(SourceFile:37)
        at net.minecraft.server.v1_6_R2.DedicatedServerConnection.b(SourceFile:3
0)
        at net.minecraft.server.v1_6_R2.MinecraftServer.t(MinecraftServer.java:5
90)
        at net.minecraft.server.v1_6_R2.DedicatedServer.t(DedicatedServer.java:2
26)
        at net.minecraft.server.v1_6_R2.MinecraftServer.s(MinecraftServer.java:4
86)
        at net.minecraft.server.v1_6_R2.MinecraftServer.run(MinecraftServer.java
:419)
        at net.minecraft.server.v1_6_R2.ThreadServerApplication.run(SourceFile:5
82)
Caused by: java.lang.NullPointerException
        at net.milkbowl.vault.chat.plugins.Chat_GroupManager.getPrimaryGroup(Cha
t_GroupManager.java:329)
        at net.milkbowl.vault.chat.Chat.getPrimaryGroup(Chat.java:732)
        at me.main.LiveChat.PlayerDisplayName.main(PlayerDisplayName.java:18)
        at me.main.LiveChat.Listeners.CommandListener.onPlayerCommandPreprocess(
CommandListener.java:38)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:425)
        ... 16 more