RSS feed broken after 2.3 upgrade

After using “Automatic upgrade” plugin to upgrade to wp2.3, my RSS feed cannot work.

http://betshopboy.net/feed/ returns HTTP/1.1 301 Moved Permanently to http://www.betshopboy.net/index.php

http://web-sniffer.net/?url=http%3A%2F%2Fbetshopboy.net%2Ffeed%2F&submit=Submit&http=1.1&gzip=yes&type=GET&ua=FeedBurner%2F1.0

Other feed links such as http://betshopboy.net/wp-rss2.php and http://betshopboy.net/wp-atom.php do not work either.

I think my wordpress installation is broken. Please HELP!