First of all i would like you to please read up on the Uniform Server License. As it is open source you have to make sure you inform your users that they are paying for your part of the product and not Uniform Server. As for your problem, Uniform Server can be ran on any Windows OS platform. Error free*. With Vista, ofcourse you have to have admin privileges to run it because of the Vista UAC. As long as they sign in from an admin account everything should be ok. They dont need to force the Run as Administrator. It should work. ;-)