Sims 3 pets and Sims 3 not working for Mac

I have Sims3, Sims3 supernatural, and Sims 3 pets and a Mac computer. I usually only played supernatural, and it's always worked and still works, but I recently bought Sims3 pets. Whenever I try to launch Sims 3 pets or just the normal Sims 3, with the correct disc in, an error code saying "No game disc found! Please insert The Sims 3 Supernatural game disc before proceeding." However, at the bottom of the Launcher, it recognizes that the normal Sims3 and Sims3 Pets have been downloaded, but neither of the Launchers actually work. I downloaded Origin and tried to play from Origin, but it does the exact same thing. I don't really understand why I'm having these issues... All three are DVD format, and are registered. The only launcher working appears to be Sims3 Supernatural, and I'm very frustrated.