You may also need to clear your cookies, the best way to find how to do it in your browser is to Google "how to clear cookies in <insert browser type e.g. internet explorer>". It is usually done in tools and internet options from the menu bar.
If you are still having trouble booking/registering submit a support request, give us a call on 1300 GET TIX (438 849) and we will be able to complete your inquiry. Be advised that there may be a processing fee incurred for phone bookings.