Sims 2 Custom Content ... ?

You need winrar or 7 zip to extract the unless they are from the exchange then you can click on it and it will install. Otherwise you need winrar and 7 zip downloaded on your computer. Once you downloaded one of the two programs you need to right click on the download and click extract here once you do that it will install into the game. And that's it. If it still not working then maybe it's something wrong with the downloads. The exchange is very buggy so I reccomend using modthesims instead the stuff isn't as buggy but be careful downloading mods though. And do you have the required expansion packs for the game that could also cause the error.