CPanel New Domain

Background Note: When I first asked this here, I was told that it is off topic and I should ask at StackOverflow. StackOverflow said it is off topic and I should ask on ServerFault. Serverfault said it is off topic and I should ask on Unix&Linux. So, I am asking again here. I am trying to add a new domain using CPanel. I went into Addon Domains and added the domain. I went into the domain's folder and added an index.html file. When I go to http://sottovoci.net , I get Template Error: The template file must be given (or the template could not be opened) I've been Googling for a week and I haven't found a solution to this problem. However, I have found that if I go to http://sottovoci.net/index.html , I get the placeholder index page that I made. Further, if I go to http://www.sottovoci.net , it defaults to the index page. If I go to http://sottovoci.net , it default to http://sottovoci.net/cgi-sys/defaultwebpage.cgi instead of using index.html. Now, having spent the weekend reading endless documentation that all says to just add the domain and it magically works, I am out of sources of information to search. Where does CPanel hide whatever setting it is that is redirecting to cgi-sys/defaultwebpage.cgi instead of index.html? How can I change it to use index.html instead of cgi-sys/defaultwebpage.cgi?