PSP CANNOT be used for editing Poser UI files. Poser uses an earlier format of PSD files, I believe, something like Photoshop 3 or 4. Photoshop or its decendent Photoshop Elements, respect this format. But PSP updates it and saves it out in the latest PSD format, which handles transpancy very differently, and results in a file which can't be read by Poser's rather old PSD file reader. This was determined back when we tweaked P5's library icon interface soon after it came out - see PoserPros Poser 5 forum for background.