I really need your help with cgi-sys/defaultwebpage.cgi

[00237casa74]

Hello, I really need help.
this is my problmeme: http://www.casa237online.co.cc
http://www.casa237online.co.cc/cgi-sys/defaultwebpage.cgi
I looked at the following link: http://x10hosting.com/wiki/Defaultwebpage.cgi, but nothing works and it lasts for almost a week.
I really do not know what to do, and more, which really worries me is that I really do not know how it happened.
This is a site in joomla 1.5
I'm a real newbie.
cordially