There was a thread similar to this before. I just ran RSS validation and this is the error I am getting thrown...
This feed is valid, but interoperability with the widest range of feed readers could be improved by implementing the following recommendations.
line 2, column 190: Use of unknown namespace: http://organizeseries.com/
Any plans to get them to support it? Feed works fine for me. I just like to have everything validate with no errors.
I did post on the Google group asking that they do btw.