Nice render !
One thing I don't understand about your problem with materials and texture maps :
AFAIK a texture is always a part of a material description.
That means that you can't have a texture mapped to your surface(s) without a material applied to your surface(s) (and AFAIK you can't have a model with no material at all).
If your problem is with the material color maybe mixing with the texture colors, then just use a completely white (255,255,255) material.