The problem is probably that you are exporting as .png (or maybe another format with alpha channel)- in which case the background and foreground are separate. I know when I tried to export with PNG some of my paint programs brought in both background and foreground just fine, some only the foreground, and Photoshop only the background with a shillouette like the above. It is actually cool to have the foreground and background separated, but confusing to some programs. Try exporting as tif or try opening the image in a different paint program to see if you get the same result.