Poser smoothing tends to screw things up. tiny bevels , unwelding polys , crease angle are all ways of convincing Poser to smooth the object in a contolled way . It takes a while to learn what your model needs to look like for Poser use.

Your questions are not stupid , and at least you are asking them and trying different things to see what works for you.

One point I didnt make before , I would really redo your uv map , the wall areas seem really small on the map I see in Lightwave. That will affect your texturing.