Glad you got it working!

But moving the PNG shouldn't make a difference. You don't really need it. (The MAT poses UTC creates don't have PNGs. Hence, you get the "shrugging man" in the library. But it should still work when you click it.)

Did you give the converted texture a unique name? Poser tends to get confused if two textures have the same name, even if they are in different folders.