If you are the webmaster of this site you should log into your account and check / remove any hidden iframes from the page. Once this is completed the page will display.
You should also change all passwords for your hosting account control panel, then scan your PC with a recent antivirus product / spyware checker, then update all php scripts on your hosting account to the most recent versions. Then you should view the following documents regarding security
http://www.google.com/search?q=mysql+injection
http://en.wikipedia.org/wiki/Cross-site_scripting
http://www.google.com/search?q=php+script+vulnerabilities
http://en.wikipedia.org/wiki/Remote_File_Inclusion
http://en.wikipedia.org/wiki/SQL_injection