Hi Suresh,
You have to clear the Sametime server ID password.
Sametime community server installer will detects whether the Domino server ID has a password.
Following technote described another scenario where ID password is not set but Sametime community server also failed to install.
IBM Sametime install fails on checking server ID password
https://www-304.ibm.com/support/docview.wss?uid=swg21515724