What were the props?  It sounds like some files are missing.

The .obj file would go into the geometries folder.   The .rsr file goes into the props folder, but there should also be a .pp2 file.

You can import the .obj file into Poser.  Go to "File" and "Import" and pick "Wavefront Object". That will import the prop into Poser.  You can then resave it to your library props folder.

"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