Material Library VX Addon - Textures doesn't load

I try to make a library with help of the Material Library VX addon. Unfortunately when assigning a material to an object, the texture isn’t loaded for some reason. The object becomes pink.
Strange is that when a material from the same library is appended of linked, it works.

Am I doing something wrong or is this a bug?

Left, the material from the Material Librayy VX Addon, right the same Material linked from the same Blend file.

Thanks in advance,