In your example, you use "addthis_button_tweet", but i can't find it in the list http://cache.addthiscdn.com/services/v1/sharing.en.xml. I don't understand why.
Sol
(AddThis Happiness Specialist)
May 14, 2012 03:23PM EDT
The Tweet button is a special button that is part of the Twitter service. Are you having a specific problem with the Tweet button? If so, please provide a link to a page where the code is installed so that I can investigate. Thanks.