ContactForm Solution Pack is not an extension therefore there is no MXP file or indeed a serial number. Just copy the files to your site, configure a few settings in the Global file and it works.
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.