I am not able to reproduce this problem, can you send a copy of the page you are validating and the style.css file so i can look into it further.
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.