Using the most recent RW version CraftTweaker throws;

[INITIALIZATION][CLIENT][ERROR] [crafttweaker]: Error executing {[0:crafttweaker]: stages.zs}: null java.lang.NullPointerException at net.darkhax.itemstages.compat.crt.ActionItemStage.<init>(ActionItemStage.java:29) at net.darkhax.itemstages.compat.crt.ActionAddItemRestriction.<init>(ActionAddItemRestriction.java:20) at net.darkhax.itemstages.compat.crt.ItemStagesCrT.addItemStage(ItemStagesCrT.java:21) at Stages.__script__(stages.zs:827) at __ZenMain__.run(Stages) at crafttweaker.runtime.CrTTweaker.loadScript(CrTTweaker.java:221) at crafttweaker.runtime.CrTTweaker.loadScript(CrTTweaker.java:101) at crafttweaker.mc1120.events.CommonEventHandler.registerRecipes(CommonEventHandler.java:68) at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_1167_CommonEventHandler_registerRecipes_Register.invoke(.dynamic) at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90) at net.minecraftforge.fml.common.eventhandler.EventBus$1.invoke(EventBus.java:144) at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:182) at net.minecraftforge.registries.GameData.fireRegistryEvents(GameData.java:787) at net.minecraftforge.common.crafting.CraftingHelper.loadRecipes(CraftingHelper.java:623) at net.minecraftforge.fml.common.Loader.initializeMods(Loader.java:742) at net.minecraftforge.fml.client.FMLClientHandler.finishMinecraftLoading(FMLClientHandler.java:336) at net.minecraft.client.Minecraft.func_71384_a(Minecraft.java:534) at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:377) at net.minecraft.client.main.Main.main(SourceFile:123) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at net.minecraft.launchwrapper.Launch.launch(Launch.java:135) at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

This was for Tinker I/O solid fuel.

Falling back to 2.6.1 resolved issue.

Please let me know if this is on T/IO or CraftTweaker side.