Can you please share your experience and knowledge on this issue?

Our current system is DB2 UDB V8.2 /Win 2003
Cluster enviornment

When I failed over from Active node to passive node (in the cluster) , the cluster group was failed over successfully to the passive node.
But when I failed over the DB2, It was moving to the passive node then on the half way it was failed back to primay node automaticaly.

I have compared the windows services on the both nodes and the
DB2DAS-DB2DAS00 service is missing on the Passive node.
Also I can see two errors in the event log.

Cluster resource 'DB2DAS00' in Resource Group 'DB2' failed.
Cluster generic service 'DB2DAS00' could not be found.

Do I need to create the DAS again ? or something else?

Can someone assit me please?