This could be either a webserver setup issue, a Contribute
setup issue or both.
When you go to your home page, you are probably going to:
http://www.whateveryourdomainis.com/
and Contribute can't currently pick up the home page, which
should be recognised as the 'default' page.
If you are on a Windows web server, the home page is normally
default.htm, so you have to add something like index.html into the
list of default docs on IIS.
I think there is also somewhere within Contribute where you
can set what the default doc, in this case index.html, should be
for the site, so try doing that as well.
If you fix it, please tell us here what you did.
Thanks
lukaro