I can't import vray materials in sketchup

Hello everyone! i’m having problems with importing vray materials to sketchup 2015
i downloaded a material from http://www.vray-materials.de/ , clicked on the M button in sketchup → scene material → create material → standard
then right click on default material → import material → folder with downloaded vray material. But the folder seems to be empty…

When i open the folder directly from my desktop, the material exists, and the extension of the material is .mat and it opens with microsoft access.

Is anyone having the same problem? How can i fix this?

Thanks in advance