'Failed to open page' due to port problems on a Mac

This has, I am sure, a simple fix; I just don’t know what it is.

I recently upgraded from Tiger to Leopard. Now, when I try to access my blog (I am running it locally while I work the kinks out) I get a “failed to open page” error, that “Too many redirects occurred trying to open “http://localhost/”. ” The site url is defined in the admin panel as localhost:80, but for some reason, the “80” is being dropped, even if I type the address in manually.

All of the web pages and whatnot are where they are supposed to be in the htdocs (sub)folder/s.

What is the fix?

Thanks