Hi there Tigerskin.
Have you tried clearing your caches? Unfortunately, I can't really help you if the problem is related to third party CC, but if it's just store content, then clearing your caches may help. Go to your Sims 3 folder, and there should be a few files titled CASPartCache, compositorCache, scriptCache, and simCompositorCache. Delete these but make sure to leave the rest, including socialCache, untouched. Let me know if this helps or not.