Why can´t I apply my saved shaders to my object?

I´ve built some shaders and tryed to save them using the matlib add-on (current build), which has all worked pretty much how it should. Now I reloaded the shaders from my library to apply them to my model, but it doesn´t work. I just get the info from blender that “applying is disabled for the material preview object”.
When I try to render, the object that I wanted to apply my shader to is invisible, though being enabled for rendering.
How can I get this to work?

Cheers and thanks for answers!

you should ask it at this thread
but I think it has to do with not have saved the present file before…:confused: