It sounds like Tenkoku cannot find one of it's internal objects. Make sure the Tenkoku/TenkokuLibrary object in your scene is not missing any shaders (there should be 22 int he list) or static objects. If you do see anything missing perhaps replace the Tenkoku prefab in your scene with a new one from the project, or try reinstalling Tenkoku from scratch, perhaps there was an install glitch.