Normals forward is a fix that ideally should be fixed in the modeller.

I use Lightwave and have never had a problem with Poser flipping polygons. I do not use the import option though to make polygons consistant.

Polys can show black in Poser if they are not planar or if they are double sided.

Applying a small amount of bump will often fix co-planar polys.

If you can post a picture of the problem area , or send the mesh to someone who can check it people can give you better suggestions.