I had downloaded photoshop elements 6 for mac and used the trial period. It ran up and my mother purchased the program on a disc. When I try to install it it starts the setup and then tells me that an error occurred and there is an incompatible payload or something along that line. What do I need to do to fix it. I know I should have just put in the s/n from the box instead of trying to install with the disc but I didn't think that much. Also I have sent the downloaded trial version to the trash but it doesnt' seem to help. any help?