No, iRite is not CS5 compatible, neither is Universal Email 3.
you should keep Dreamweaver CS3 installed to be able to use the previous versions of the extensions.
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.