Repeated attacks on the site may have resulted in your username being reported as blocked by the site. In every reported case the username has not been blocked. Please accept our apologies.
To resolve the issue, please clear your cache and cookies. If you are unfamiliar with clearing cache and cookies please review instructions.
To clear the cache please visit this University of Indiana page that addresses a variety of browsers, with screenshots: http://www.wikihow.com/Clear-Your-Browser%27s-Cache
You may also want to update your java version.
To see what version of Java you have and some details about it, visit this link: http://java.com/en/download/installed.jsp and click on the 'Verify Java Version' button.
If Java is out of date that page is the right place to be and it can help you to update Java on your computer.