[14:08:51 ERROR]: Could not pass event InventoryClickEvent to VillagerShop v0.1
org.bukkit.event.EventException
at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:305) ~[craftbukkit.jar:git-Spigot-2f787bd-ea28011]
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[craftbukkit.jar:git-Spigot-2f787bd-ea28011]
at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [craftbukkit.jar:git-Spigot-2f787bd-ea28011]
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [craftbukkit.jar:git-Spigot-2f787bd-ea28011]
at net.minecraft.server.v1_8_R2.PlayerConnection.a(PlayerConnection.java:1614) [craftbukkit.jar:git-Spigot-2f787bd-ea28011]
at net.minecraft.server.v1_8_R2.PacketPlayInWindowClick.a(SourceFile:31) [craftbukkit.jar:git-Spigot-2f787bd-ea28011]
at net.minecraft.server.v1_8_R2.PacketPlayInWindowClick.a(SourceFile:9) [craftbukkit.jar:git-Spigot-2f787bd-ea28011]
at net.minecraft.server.v1_8_R2.PlayerConnectionUtils$1.run(SourceFile:13) [craftbukkit.jar:git-Spigot-2f787bd-ea28011]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [?:1.8.0_45]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_45]
at net.minecraft.server.v1_8_R2.SystemUtils.a(SourceFile:60) [craftbukkit.jar:git-Spigot-2f787bd-ea28011]
at net.minecraft.server.v1_8_R2.MinecraftServer.A(MinecraftServer.java:710) [craftbukkit.jar:git-Spigot-2f787bd-ea28011]
at net.minecraft.server.v1_8_R2.DedicatedServer.A(DedicatedServer.java:368) [craftbukkit.jar:git-Spigot-2f787bd-ea28011]
at net.minecraft.server.v1_8_R2.MinecraftServer.z(MinecraftServer.java:651) [craftbukkit.jar:git-Spigot-2f787bd-ea28011]
at net.minecraft.server.v1_8_R2.MinecraftServer.run(MinecraftServer.java:554) [craftbukkit.jar:git-Spigot-2f787bd-ea28011]
at java.lang.Thread.run(Thread.java:745) [?:1.8.0_45]
Caused by: java.lang.NullPointerException
at net.dipselmedia.VillagerShop.Menu.onCathegoryChoose(Menu.java:29) ~[?:?]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_45]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_45]
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:301) ~[craftbukkit.jar:git-Spigot-2f787bd-ea28011]
... 15 more