[Current Issue] Sims 3 "serious error" when loading save

I have never had a problem plaing the sims 3 till now. I just dowloded the sims 3 on my new computer along with the 4 expansion packs that I have, but every time I go to load into the world I am hit with a very whited out screen and a message that says. " A serious error has occurred while loading sunset valley.sims3'. It is strongly recommended that you restart the application." This only happens when i have any of the expansion packs downloaded. It works fine when its just the sims 3 game its slef. Does anyone know why this is happing.