I use multiple runtimes. What I did for Poser 5 was to make a separate runtime for it and then just add the runtime to the library. I had no trouble accessing the materials in the folder in the material room.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi