The SQL Server Service Broker for the current database is not enabled, and as a result query notifications are not supported

If just in case u found an error something like this

The SQL Server Service Broker for the current database is not enabled, and as a result query notifications are not supported. Please enable the Service Broker for this database if you wish to use notifications

then u must enable it

it's effected SQL SERVER 2005 and above

ALTER DATABASE DB_NAME_HERE SET NEW_BROKER WITH ROLLBACK IMMEDIATE
ALTER DATABASE DB_NAME_HERE SET ENABLE_BROKER

-- to check whether the broker already enabled or not (1 = enabled, 0 = disabled)
SELECT is_broker_enabled FROM sys.databases WHERE name = 'DB_NAME_HERE '