(some .....bad english ;-) )

i'm just sign up and take some free x10hosting and i try to make my first site

just i edit the index.html on webroot directory (from cpanel editor) but when i 'm going in my domain with firefox
auto redirect me to " http://staff.x10hosting.com/default.web.page/"

and say :
Server Error
There has been a server error. Please try again momentarily.

IS THIS A PROBLEM OF THE SERVER OR BECAUSE MY LAME USE ?
THANKS A LOT :-)