To others: Before your curiosity gets the best of you and you decide to check this guy's site, please be aware that may be not suitable for work at some places. Update: I don't have privilege to edit the URLs statement that was added to the question, so I'll just update here: The site is not an adult site in the classic sense, but one of those on how to get girls. Still, some of the pix on the front page are a bit racy, so if you're at work, I still recommend staying away.
Check your server software's configuration. It may be pointing port 443 (https) to a different default directory than port 80 (http). If so, you'll need to change the default directory for port 443 to match that of port 80.
If you're using Apache, I expect there are files named httpd.conf and ssl.conf somewhere, possibly in separate directories. (Most likely these directories will be at the same level or one will be a sub-directory of the other. Possible starting points are /etc/httpd/ and /usr/local/apache2/. These directories are usually named conf and conf.d.) Both files probably have entries for DocumentRoot (although the one in ssl.conf may be commented out with a "#"). If neither is commented out and they don't match, change the one in ssl.conf. See the Apache web site for more detail.
I've only used Apache, so I can't help with other servers.
And you probably know this, but I should mention it for completeness: Don't forget to make back up copies of your existing configuration files before you edit them! That way, if your changes don't work, you can go back to what you have.
Edit: I missed that this was Joomla, which I've never used. So, I'm not sure if this will be useful or not.