StackableItems Error

2012-10-09 17:59:42 [SEVERE] Could not pass event CraftItemEvent to StackableItems
org.bukkit.event.EventException
	at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:341)
	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.NetServerHandler.a(NetServerHandler.java:1108)
	at net.minecraftserverhook.NetServerHandlerProxy.a(NetServerHandlerProxy.java:190)
	at net.minecraft.server.Packet102WindowClick.handle(SourceFile:29)
	at net.minecraft.server.NetworkManager.b(NetworkManager.java:282)
	at net.minecraft.server.NetServerHandler.d(NetServerHandler.java:109)
	at net.minecraft.server.ServerConnection.b(SourceFile:35)
	at net.minecraft.server.DedicatedServerConnection.b(SourceFile:30)
	at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:577)
	at net.minecraft.server.DedicatedServer.q(DedicatedServer.java:213)
	at net.minecraft.server.MinecraftServer.p(MinecraftServer.java:473)
	at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:405)
	at net.minecraft.server.ThreadServerApplication.run(SourceFile:539)
Caused by: java.lang.NullPointerException
	at org.bukkit.craftbukkit.inventory.CraftItemStack.setAmount(CraftItemStack.java:114)
	at haveric.stackableItems.SIPlayerListener.craftItem(SIPlayerListener.java:162)
	at sun.reflect.GeneratedMethodAccessor71.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:339)
	... 15 more