19:57:05 [SEVERE] Could not pass event InventoryClickEvent to DtlCitizensTrader v2.4.0
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.SimplePluginManager.fireEvent(SimplePluginManager.java:477)
	at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:462)
	at net.minecraft.server.v1_4_R1.PlayerConnection.a(PlayerConnection.java:1186)
	at net.minecraft.server.v1_4_R1.Packet102WindowClick.handle(SourceFile:31)
	at net.minecraft.server.v1_4_R1.NetworkManager.b(NetworkManager.java:290)
	at net.minecraft.server.v1_4_R1.PlayerConnection.d(PlayerConnection.java:113)
	at net.minecraft.server.v1_4_R1.ServerConnection.b(SourceFile:39)
	at net.minecraft.server.v1_4_R1.DedicatedServerConnection.b(SourceFile:30)
	at net.minecraft.server.v1_4_R1.MinecraftServer.r(MinecraftServer.java:598)
	at net.minecraft.server.v1_4_R1.DedicatedServer.r(DedicatedServer.java:224)
	at net.minecraft.server.v1_4_R1.MinecraftServer.q(MinecraftServer.java:494)
	at net.minecraft.server.v1_4_R1.MinecraftServer.run(MinecraftServer.java:427)
	at net.minecraft.server.v1_4_R1.ThreadServerApplication.run(SourceFile:849)
Caused by: java.lang.NullPointerException
	at net.dtl.citizens.trader.types.Trader.isWool(Trader.java:487)
	at net.dtl.citizens.trader.types.Trader.isSellModeByWool(Trader.java:390)
	at net.dtl.citizens.trader.types.Trader.getBasicManageModeByWool(Trader.java:399)
	at net.dtl.citizens.trader.types.ServerTrader.managerMode(ServerTrader.java:899)
	at net.dtl.citizens.trader.NpcEcoManager.onInventoryClick(NpcEcoManager.java:175)
	at sun.reflect.GeneratedMethodAccessor202.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.java:425)
	... 14 more