Here's a possible answer. Poser has a few problems with normals in 3DS files. About the only thing you can do is bring the 3DS file into MAX, Cinema4D, Lightwave, Maya, or something in this line, and check to see what the normals are doing. If you don't know what a normal is - here's a quite def. It basically means which why the poly is facing. Polys in 3DS files are 2 sided. Sometimes they can get flipped over. This can cause your black spots.