Is this all surfaces except (some) skins? It looks as if the images are not being read correctly or the shader (that tells Iray how the surface behaves) is bad. Skin on recent characters tends to use the PBRSkin shader, while many clothes and older characters use the Iray Uber Base. It may be worth reinstalling a fresh download of the Default Resources, which should repalce any bad shaders if the problem is general.