RSS not properly validating (with feedwordpress)

I am running FeedWordPress 0.97 and WordPress 2.0. I’m not sure which is the cause, but somehow, I am producing an invalid feed.

The error is coming from an aggregated item from feedwordpress. The original source feed is from Yahoo and is valid — http://sports.yahoo.com/nfl/teams/den/rss.xml

This link shows the error returned by Feed Validator — http://feedvalidator.org/check.cgi?url=http%3A%2F%2Fwww.orangeandblueblog.com%2Fnewsfeed%2F%3Ffeed%3Drss2

So, somewhere along the line, WordPress is taking a valid feed entry and making it invalid…