Hello Aman
We discussed on the phone that you have some scenarios where the Checkpoint Firewall is UP and you're still seeing events "unable to read tunnelState" attribute. When this occurs, please check MIB tools to see if the tunnelState instance that is being monitored by the Watch is still an active instance within the tunnlState table.
I will open a case for you and send you an email on this topic.
Thank you,
~Jay V