Bukkit

Using HGGifts 1.0 and CB 2170 I got this when, by the console reading I think a player logged before his gift was received or totally sent to him. Anyway, here's the error it threw.

02:09:07 [SEVERE] Could not pass event InventoryCloseEvent to HGGifts
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:303)
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:459)
        at net.minecraft.server.NetServerHandler.handleContainerClose(NetServerHandler.java:1048)
        at net.minecraft.serverhook.NetServerHandlerProxy.handleContainerClose(NetServerHandlerProxy.java:192)
        at net.minecraft.server.Packet101CloseWindow.handle(SourceFile:16)
        at net.minecraft.server.NetworkManager.b(NetworkManager.java:229)
        at net.minecraft.server.NetServerHandler.a(NetServerHandler.java:113)
        at net.minecraft.serverhook.NetServerHandlerProxy.a(NetServerHandlerProxy.java:83)
        at net.minecraft.server.NetworkListenThread.a(NetworkListenThread.java:78)
        at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:551)
        at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:449)
        at net.minecraft.server.ThreadServerApplication.run(SourceFile:492)
Caused by: java.lang.NullPointerException
        at com.precipicegames.lachy2901.hggift.HGGiftListener.onInventoryClose(HGGiftListener.java:37)
        at sun.reflect.GeneratedMethodAccessor290.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:301)
        ... 12 more