Team Explorer has collaboration tools that enable it to interact with Windows Live Messenger or Office Communicator. If you deleted them, you may get the same error from Team Explorer, which is trying to talk to a program that does not exist. In Team Explorer, right-click on the members of the group, select "Personal Settings". In the "Collaboration" section, click "Edit" and select (or place it to another provider if you want).
It worked for me.
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