Please note, if you didn’t receive an error message at the bottom of the sign up page when you used it, you do not have to worry… your sign up has been received. This message is for those who tried to sign up but were unable to do so because the page kept asking you to enter information you had already entered!
Thanks go to Arend Pijls from http://www.webplay.be/ for spotting an error with the Beta Signup form and for taking the time to let me know what was happening.
After some investigation it turns out that on some browsers (Firefox was one), the Super-Cache plugin was presenting an older version of the form page which was causing the form to give an error that a required field was not filled in! This was caused by Super-Cache not providing the latest page to some browsers.
It has now been fixed and is working properly. Apologies to anyone who tried to sign up to the beta and was prevented from doing so because of this bug.