This is a common error, but one I thought went up with an update...I could be wrong though.
What patch is your base game?
To vheck what patch you have...
For PCs: open your launcher and hover over the little base game icon
More Details can be found here: http://sims3.crinrict.com/en/2011/01/tutorial-how-to-find-your-game-version.html
For Macs: http://bluebellflora.com/ts3-on-a-mac/checking-which-patch-version-youre-running
Version
16.0.136.021001
That's not your base game version. Follow the instructions I posted please. We are just looking for the base game patch number.
Ah!...I missed the little number
1.50.56.021001
