By default, when a stand-alone instance of Microsoft SQL Server exists in a cluster environment, the SQL Server-based instance is set to start automatically. If the host node is rebooted, you may receive the following error message when you issue commands that are related to distributed transactions:
ERROR: MSDTC on server ‘servername’ is unavailable.
RESOLUTION
On the server where the trigger resides, you need to turn the MSDTC service on. You can this by clicking START > SETTINGS > CONTROL PANEL > ADMINISTRATIVE TOOLS > SERVICES. Find the service called ‘Distributed Transaction Coordinator‘ and RIGHT CLICK (on it and select) > Start.
Resources:
http://support.microsoft.com/kb/822473/
http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=54705
