The Sims 3: Installing expansion packs trouble

Hi, when I tried to install the expansion pack after using winRAR, it said "This product requires an installed copy of The Sims 3. Please install the Sims 3 before installing this product." I have tried installing numerous of expansion packs and it said the same thing. Before trying this I did the "no c-d" for the Sims. Would that be the case? By the way, I have the store purchased Sims 3 game and a mac
Thanks
//Helpers edit: moved to the relevant section.
Shamrock