Toefl Online Registration Failure

Whenever I tried to register for Toelf test online, I got error message saying an error has occured?

www.toefl.org - then click on "on line registration for the toefl test", then I selected Australia -> Melbourne.

http://securereg3.prometric.com/ProfessionalHome.aspx?dispmode=TOEFL&ccode=Aus

please help. something's wrong with the website?