I have a new Atom Feed at:
http://www.holographyforum.org/phpBB2/feed.php
The other feed my have been broken in the upgrade process. In any case only the new feed will be supported.
New Atom Feed
New Atom Feed
I updated the settings, so I think the feed works a little better now. Since this feed is phpBB supported it will be much less problematic. The others were hand inserted and edited code that was stolen from other designers and modified for our use.