The items for this website may require expansion packs or meshes that haven't been included. Most items don't require a mesh or have it included, but some don't. If they require an expansion pack that you don't have, they may crash your game. When you download, create a folder for SixSixSims in your downloads folder and place these items there so that if your game crashes or a file is missing a mesh, you can figure out which file is the problem and find it easily.