Sims Custom Content won't install

My Sims 3 custom content wont install(I get mine off the exchange). It used to work but now it doesn't. Anyway, I deleted all of my cc because I wanted to start fresh.I went to the exchange trying to figure out what sims I should get. And I saw a few I like (I noticed that I have downloaded a few of them and had them on my game before I deleted everything). So I tried to hid "Add to Game" or whatever and It didn't do anything. This is how I usually added cc so this was weird. So I then proceeded to hit "Save File" so i could just put it in my downloads folder. I did this, it worked. And I tried to install and it gave me this message "Installation failed: Please make sure your game has the latest Software Updates and try again." But my game is updated. Please help! Devil
P.S. I have a iMac. If that helps