[Radiant] rss_behavior plugin

[BJ Clark]

Hello all.
I'm trying to use the rss_behavior to display my mephisto blog's rss
feed on my radiant site.
I've installed rss_behavior via script/plugin install etc.
i've installed ruby-feedparser
I am getting the following error in my page when it's rendered:
"undefined tag `feed'"

I'm not getting errors in:
production.log
lighttp.error.log
lighttp.access.log

The code I'm using in my page is:
 <dl>
 <r:feed:items url="http://www.robotdeathsquad.com/blog/feed/atom.xml"
limit="3">
  <dt><r:feed:link /> - <r:feed:date /></dt>
  <dd><r:feed:content /></dd>
 </r:feed:items>
 </dl>

I am NOT using a specific behavior.

Anyone have any ideas on troubleshooting?