Sims 3 Expansion Packs Glitching

Every time I try to play the Sims 3 with my expansions packs installed the screen glitches so badly. I get through the launcher and main menu then while a world is loading the it glitches so much that most of the time the screen just goes black. I play on my MacBook Pro and I have the 64-bit version of the base game. Why won't my packs work? I've had them since I was a kid and just want to play them again!