Hi Andrei,
Thanks a lot for the help. The requirement was to display an error message let it be in the pop up or as a bsp message. The first solution of using javaerrorhandler( ref_jexception ) was not working. I had already tested it. The second solution that you gave certainly helped in solving the problem.
I used the event client_user_state_message that is being already raised in the listener.
After that I enhanced the method ACTION_HANDLER of class CL_CRM_MCM_SESSION.
Thanks,
Biswajit