Hey and welcome to forums, Hayesbiz.
schmidthouse, the title of the topic says Avast Free so i suppose the version it's 5.0.xxx or 5.1.xxx.
Hayesbiz, did you filled up all the obligatory spaces on the form? If you did and continues not to work, I recommend to try a online registration if actually the registration via GUI doesn't work.
You can do the online registration, here:
http://www.avast.com/registration-free-antivirus.phpWaiting for your feedback.