I'm using XP sp 3, the exact message is 'the serial number you entered is invalid. please try again. if the problem persists, contact customer support.
I've tried upgrading and a clean install, but get the same message.
What previous versions did you have of Adobe products already installed on your windows XP?
What is the license type of your previous product and what was the name of product?
Did you purchased for Dreamweaver CS6 license for a single machine (Retail) or multiple machine (Volume)?