You can enable cookies in your internet options, or try using a different browser such as Google Chrome or Firefox. You may also need to clear your cookies. To do this it is different in different browsers.
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 in the menu bar.
If you are still having trouble booking/registering please submit a request to our online Tix Support service.