Error Message when try to load Appaloosa Plains

I just bought The Sims 3: Pets off of the Origin store as a PC Download. I downloaded and installed my game and made sure that everything was up to date. However, when I try to start a game with Appaloosa Plains, I get an error message reading. " A serious error has occurred while loading 'AppaloosaPlains.world'. It is highly recommended that you restart the application."

I tried quitting the game and restarting and nothing. Still the same message. I have checked to make sure my game is updated using the launcher and I am now at a loss. 🙂 I had also bought Night Life at the same time as Pets and that one works fine. It is just Appaloosa Plains. Any help would be awesome! Thanks!!