Hi
Sounds as though your downloads may be corrupt or incomplete. Unfortunately this happens fairly frequently with Origin, but you should be able to get it working. The first thing to check is that your Mac is sufficiently up-to-date to be able to run the Origin client. It requires at least OS X 10.6.8 with an Intel Core 2 Duo processor or better.
Try deleting and reinstalling the Origin client for Mac and make sure it is up-to-date. The latest version can be downloaded from here: http://www.dm.origin.com/mac/download
Additional advice on how to download games (thank you Tremayne for this tip):
When downloading from Origin, do NOT use the first install icon. Move your cursor over the game cover and click on the information (letter i) and then click on the install button from there.
Are you running anti-virus software or any clean-up applications? If so, disable these, as they might be deleting files that Origin needs!
For some reason, downloads from Origin frequently become corrupted. Using the i reduces the chance of your download being corrupted. If you have already been unfortunate and have a corrupted download, then it is important to remove all traces of this before trying again, by doing a thorough, clean uninstallation first.
If this doens't work, try starting from scratch, by not only reinstalling the Origin client but also the game. BluebellFlora's website provides a guide on how to do this: http://bluebellflora.com/the-sims-3-on-a-mac/how-to-do-a-clean-uninstall-and-reinstall-on-a-mac/
After cleanly uninstalling, install the base game and patch it up to date. If you cannot update via the Launcher, download and apply the latest cumulative manual patch (called the superpatch) for Mac.
Check that your game works properly. Then install any EPs and SPs that you own, in order of release date.
Caspin
