I can go directly to a feed in Firefox by entering the URL, for example: http://hrvarsity.com/photopost/external.php?type=RSS2
But when I click the orange "feed" icon at the right end of the URL address bar in FF, I get an error. It works fine in IE7.
It looks like FF is inserting an extra "http//" in the address. If I remove this extra text, it works. You can try it at http://hrvarsity.com/photopost/
if you like.