"The AO image was created by adding an ao node to the face and body texture of aiko" The purpose of AO is to produce "soft shadows", but your lighting in that scene does not compliment the use of it. You should try using IBL (image based lighting) on the light with AO. I dont think you have that light set as a diffuse IBL. Also, you can play with AO strength and (in the AO scene options for your light) try lowering the max distance a bit, while increasing samples slightly to get rid of artifacting.

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Tools :  3dsmax 2015, Daz Studio 4.6, PoserPro 2012, Blender v2.74

System: Pentium QuadCore i7, under Win 8, GeForce GTX 780 / 2GB GPU.