java.lang.NullPointerException: Updating screen events
        at moze_intel.projecte.gameObjs.container.inventory.TransmuteTabletInventory.func_70305_f(TransmuteTabletInventory.java:389)
        at moze_intel.projecte.gameObjs.container.TransmuteTabletContainer.func_75134_a(TransmuteTabletContainer.java:137)
        at net.minecraft.client.gui.inventory.GuiContainer.func_146281_b(GuiContainer.java:687)
        at moze_intel.projecte.gameObjs.gui.GUITransmuteTablet.func_146281_b(GUITransmuteTablet.java:88)
        at net.minecraft.client.Minecraft.func_147108_a(Minecraft.java:780)
        at net.minecraft.client.entity.EntityPlayerSP.func_71053_j(EntityPlayerSP.java:337)
        at net.minecraft.client.entity.EntityClientPlayerMP.func_92015_f(SourceFile:172)
        at net.minecraft.client.entity.EntityClientPlayerMP.func_71053_j(SourceFile:166)
        at net.minecraft.client.gui.inventory.GuiContainer.func_73869_a(GuiContainer.java:648)
        at net.minecraft.client.gui.inventory.GuiContainer.public_func_73869_a(GuiContainer.java)
        at codechicken.nei.guihook.GuiContainerManager.callKeyTyped(GuiContainerManager.java)
        at codechicken.nei.guihook.GuiContainerManager.keyTyped(GuiContainerManager.java:474)
        at codechicken.nei.guihook.GuiContainerManager.handleKeyboardInput(GuiContainerManager.java:464)
        at net.minecraft.client.gui.inventory.GuiContainer.func_146282_l(GuiContainer.java)
        at net.minecraft.client.gui.GuiScreen.func_146269_k(GuiScreen.java:276)
        at net.minecraft.client.Minecraft.func_71407_l(Minecraft.java:1629)
        at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:962)
        at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:887)
        at net.minecraft.client.main.Main.main(SourceFile:148)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:601)
        at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
        at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:601)
        at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:286)
        at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:376)
        at org.multimc.EntryPoint.listen(EntryPoint.java:165)
        at org.multimc.EntryPoint.main(EntryPoint.java:54)


A detailed walkthrough of the error, its code path and all known details is as follows:
---------------------------------------------------------------------------------------

-- Head --
Stacktrace:
        at moze_intel.projecte.gameObjs.container.inventory.TransmuteTabletInventory.func_70305_f(TransmuteTabletInventory.java:389)
        at moze_intel.projecte.gameObjs.container.TransmuteTabletContainer.func_75134_a(TransmuteTabletContainer.java:137)
        at net.minecraft.client.gui.inventory.GuiContainer.func_146281_b(GuiContainer.java:687)
        at moze_intel.projecte.gameObjs.gui.GUITransmuteTablet.func_146281_b(GUITransmuteTablet.java:88)
        at net.minecraft.client.Minecraft.func_147108_a(Minecraft.java:780)
        at net.minecraft.client.entity.EntityPlayerSP.func_71053_j(EntityPlayerSP.java:337)
        at net.minecraft.client.entity.EntityClientPlayerMP.func_92015_f(SourceFile:172)
        at net.minecraft.client.entity.EntityClientPlayerMP.func_71053_j(SourceFile:166)
        at net.minecraft.client.gui.inventory.GuiContainer.func_73869_a(GuiContainer.java:648)
        at net.minecraft.client.gui.inventory.GuiContainer.public_func_73869_a(GuiContainer.java)
        at codechicken.nei.guihook.GuiContainerManager.callKeyTyped(GuiContainerManager.java)
        at codechicken.nei.guihook.GuiContainerManager.keyTyped(GuiContainerManager.java:474)
        at codechicken.nei.guihook.GuiContainerManager.handleKeyboardInput(GuiContainerManager.java:464)
        at net.minecraft.client.gui.inventory.GuiContainer.func_146282_l(GuiContainer.java)
        at net.minecraft.client.gui.GuiScreen.func_146269_k(GuiScreen.java:276)

-- Affected screen --
Details:
        Screen name: moze_intel.projecte.gameObjs.gui.GUITransmuteTablet