Too bad, I don't have any problem to render the file you posted at the 2 best quality levels.
If I can't reproduce the problem, I won't be easy to fix. [:(]

From you screen captures, I see you tried to compute the images with the Advanced rendering plug-in. Could you try with Sweet Home 3D default photo creation dialog? I don't think it will change anything for you, since macfrog used this dialog too, but who knows what can happen with furtive bugs?