MULTI/SUB Object material library doesn't save materials

I am working with the xFrog trees from the autodesk seek web site. I have created individual proxies of three of the tress types. I save the first material to a tree material library and save seems fine. I move on to the next tree and make a proxy and save that material to the tree material library, but when I look at the first one I saved the icon shows all white materials. When I apply the material I have to then spend time to re-link all the materials. When I go to make the third proxy and save the material to teh tree material library now both the first and second are all white.

Anyone able to tell me what is going on here and why I seem to be having problems saving my tree materials to a library?