Make sure that any catagory/tags are included in RSS
Wither you are keeping catagories or chnaging to a more fluid tagging system please make sure that you have the tags added to the RSS:
<title>TFS 2010 Build: Dealing with the API restriction error</title>
This one was completed with a release in January (2013).
Martin Hinshelwood commented
Make sure you present the already added tags through live writer as well.. It also has the facility to edit tags from the UI