I think I know why now, although I didn't realize this could happen. I have it hosted on site5 where you can do many different sites called "domain pointers":
A domain pointer is a domain name that points to a directory in your site. Each domain pointer can either point to the same directory as your main domain name, or have it's own separate document root within your main site.
Domain pointers let you to give the appearance of multiple web sites, while only maintaining a single hosting account. You are, as always, responsible for transferring your domain name over to our DNS servers. Your domain pointers will all use the same IP address as your main account.
Plus I don't think I have the .htaccess file right yet so I probably caused this. Do you think?