WPOso on "Redirected too many times"

I recently installed my first WordPress site with no major problems. I just installed WordPress on a second site. The home page displays fine, but when I click the link to the Dashboard, I get an error message saying I've been redirected too many times.

The standard fix appears to be clearing the browser's cache. So I just tried a different browser (Opera), with the same results. When I cleared Opera's cache, the problem was still there.

What's going on?

I think I more or less fixed it. I discovered that I can access the Dashboard @ http://www.fifthrepublic.org/wp-admin/index.php For some reason, when I click on the Dashboard link while on the home page, it takes me to http://www.fifthrepublic.org/wp-admin - I just need to add /index.php.