Site Import v2 is not compatible with Dreamweaver CS4. You will need to upgrade to Site Import v3 to use it in Dreamweaver CS4.
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.