I tried this with no success, but I did find something that did work. First I completely uninstalled the game and deleted the game registry as suggested. Then I redownloaded the installer and ran that as administrator and also ran the game as administrator. After that everything seemed to be working fine, the world editor was saving properly and I was able to upload images to my gallery. Unfortunately, that didn't even last for a day as both of those things have stopped working for me again.