There's no compromise in the download.
I get an already installed message when I visit forumdoctor.com/wp-admin/install.php
"You appear to have already installed WordPress. To reinstall please clear your old database tables first."
This appears to work just fine: forumdoctor.com/wp-admin/
..as does this: forumdoctor.com/
What exactly is the issue?
[edit] I notice from your screenshot that you also appear to be logged into the admin area of talkingreds/blog/ while doing your other install. Any difference when you log out of that site, clear your browser cache then retry the forumdoctor.com site?
[re-edit] without knowing what you've done for a database on the new site, inspect the information you entered in the wp-config file. Make sure the database you created for the new site is correct entered in wp-config. If you've imported a database from a different site, or are using a previously created database for a new installation, I suppose those could also be potential areas of conflict.