Hi Sunish,
COM errors are usually attributed to database issues in the cluster. Have you checked the replication status using DBLHelper?:
http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_tech_note09186a00801e7ddf.shtml
You can also try the following and see if it helps:
In the Cisco CallManager server, choose Start > Programs > Administrative Tools > Component Services.
Click on the plus by Component Services.
Click on the plus by Computers.
Click on the plus by My Computer.
Click on the plus by COM+ Applications.
Right-click on DBL and choose Shutdown.
Right-click on DBL and choose Start.
Open a DOS window and type iisreset, then check if IIS admin and WWW services are in the started state.
Other than this, have you tried re-booting the cluster?
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