I am having a couple problems. One is that I am unable to open certain photographs, for unknown reasons. When I try to open the image either from Adobe or from the image, it won't appear. The second problem is when I have an image in the program and I try to work with it an error message appears, "Could not complete request because the active layer is empty." The layer selection at the top of the screen is grayed out. I have a PC with Windows 8.1. How can I fix this problem?