Which version of CSS Sculptor are you installing? Are you installing version 3.0.1? If not, then the version is not compatible with CS5 and you should try going to your downloads and getting 3.0.1 to install.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.