SolitudeTraveler

Also, the failed to create menu type error that SolidRoyalty described is due to not registering the container of your tile entity in your ClientProxy. You need ScreenManager.registerFactory(ModBlocks.YourContainerType, YourScreen::new) for each GUI you'd like to create.

I had the same error and I was able to fix it by initializing the proxy. Did you do proxy.init() in your mod file's setup(final FMLCommonSetupEvent event) function?