I have a basic blog on wordpress. However, now I want to set up an actual website for my business, using wp. I purchased my domain name on wp, and then chose a host server. Last night I installed wp onto my host server (hostgator). I then received an email that says this:

Your new WordPress site has been successfully set up at:
http://mydomainname.com/
You can log in to the administrator account with the following information:
Username: admin
Password: ---------------

But when I go to http://mydomainname.com/wp-admin, and try to login with this info, I get the following error: You attempted to login with the username 'admin' on WordPress.com. If you were trying to access your self hosted WordPress.org blog, try yourdomain.com/wp-admin/. If you can’t remember your WordPress.com username, you can reset your password by providing your email address. If you have any questions please contact support.

Can you tell me what I am doing wrong? Is this happening because I originally purchased the url through wp and it's pointing to the wrong place? I am a complete newbie at this, and any info or suggestions you can provide would be SO appreciated!