Questions from me 
 Do you have the meshes? Are you downloading cc that needs you to have an EP you don't have? Do you have the latest 
CEP file (Color Enabler Package)
Make sure you are extracting to 
My Documents/EA Games/The Sims 2/Downloads, and that your Downloads file is spelled exactly as I have it spelled, capital 'D' at the beginning and small 's' at the end.