Wow, I'm bummed that they're not working. I can give you the specifics (e.g, link to download pattern from exchange, style of wall used, and color hex number for the lower part of the wall) if you want to duplicate any of these designs yourself. I'm really sorry you've had trouble with them.
Oh, I just thought of something - are you looking under the wallpaper tab in the building screen? I saved these as wallpapers, not as paints, so could you please check to see if they are there? If they still don't show up on that tab then I will probably remove the files from the swap shop because I don't want to get people frustrated.