So, from the Python Scripts panel -> Prop Samples -> Buckey Ball. Would that be a more usable item? No external programs needed if so.
Yes, those will work as well. You may want to subdivide the Buckey Ball, export to OBJ, and then import it back into Poser for a higher-res version. I am making my GeoSphere available to everybody above, so that might be a better pick, and you can do the same subdivision process with it when needed.
I tried Blender's icosphere and it was a no-go, at least with my attempts. Maybe you'll have better luck...if you do, I will be interested in your method!
I wonder why it didn't work. Poser tends to be very picky about geometry, so we have to be sure the model is clean and properly exported. I have tried exporting an IcoSphere from 3DSMAX to Poser, and it has works all the same. Maybe it's something about the exporting parameters you have used? I am guessing here.
OK, that was easy, but I noted too things. First leaving the origin as is, it loads in Poser half way through the ground, so I reset the origin to the bottom vertex, and then when it's imported into Poser it's sitting right on the ground.
You can load Dawn's OBJ to use as size reference in your 3D application scene. This way you know what size it will be in Poser. It's a good idea to move props above the ground in the modeling application, and then bake the transforms to make it permanent. In 3DSMAX, I move the origin (pivot) to (0,0,0) and bake it before exporting. When loaded into Poser, it will reset the pivot back to the center, but the prop will remain above the ground.