I imported a VRML model and proceeded to apply material with texture. I have noticed that one section of this model, when viewed from a specific perspective, does not get textured - you can see right through it. Does this have someting to do with the direction of the normals and OpenGL? Anyone see this for themselves?
Try recalculating the normals with CTRL+N.
If that does not work, then I have no idea.
Are you in potatoe mode, (ALT+Z), or just on render?
BgDM
Make sure you have the DoubleSided option ON (in the Edit Buttons window F9)
Martin
Tried both ideas. Neither worked. Very odd. I might have to go back to the original model and re-export VRML.
If you find out let me know. I am having a devil of a time with Rick Kimball’s wrl2export.py
www.kimballsoftware.com/blender/
It EXPORTS blender meshes as vrml files. The only problem is that it does not export blender materials. You have to use uv texturing or vertex/face painting.
I discovered on my own that you have to keep whatever lights you have in the blender scene very low and use almost NO specular or hardness or everything will come out pure white.
I know this is the opposite of your problem i.e. you are importing into blender rather then exporting from it but keep me aprised anyway.
Models from apps other than Blender may not have the same mesh geometry so you may have to go in there and build some faces and edges. Also, if you hit subsurf you may find that the individual submeshes collapse around the edges which means having to join then vert by vert rather than J.
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No wonder it wasn’t texturing the faces. There were none! Couldn’t see this at first because of the complexity of the model (about 36K polys), but when I examined it in the original application (Rhino) I discovered that a NURBS surface was missing. 
you can also loose faces from vrml to blender if they have more than 4 sides
(blender only supports 3 and 4 sided faces)