After doing some search i saw a post that said you just have to run the below from query analyzer:
ALTER DATABASE DatabaseName SET ENABLE_BROKER;
But the query kept running for minutes and never stopped.So i taught there must be some conflicts.
So i started looking for a way to force the close off conflicting sessions.
So i ran
ALTER DATABASE DatabaseName SET NEW_BROKER WITH ROLLBACK IMMEDIATE;
and then
ALTER DATABASE Databasename SET ENABLE_BROKER;
and then the query ran successfully
make sure you run:
SELECT is_broker_enabled FROM sys.databases WHERE name = 'DatabaseName'
to get the correct value : is_broker_enabled = 1