An error occurred while enlisting in a distributed transaction error while trying to connect with eConnect
Some searching found this tool:
http://www.microsoft.com/downloads/details.aspx?FamilyID=5e325025-4dcd-4658-a549-1d549ac17644&DisplayLang=en
Its called 'DCP Ping' - it will allow you to ping the other DCP box and make sure that there is not a firewall in the way.