Does your texture have a bit of transparency? Check your TGA file to be sure that there's no Alpha layer.
White is the default color of a plain mesh (a mesh without transparency or color). Thus, I think that if the texture is badly mapped on the mesh, the "background" of the mesh (here, white) will be show. So, also check your UV mapping of the texture on the model to be sure that no vextex lack UV mapping.
It's juste some suggestions, maybe it is a bug of course