与YII连接时数据库mysql代理错误

I have configure mysql cluster with one master and one slave. Configured mysql proxy as common ip to access the servers. when i connect using mysql command its successfully connecting. But when i tried to access mysql proxy in yii application I am getting following error

2011/12/01 05:25:40 [error] [exception.CDbException] SQLSTATE[42000] [1049] Unknown database 'PortalDB' 2011/12/01 05:25:40 [error] [exception.CDbException] exception 'CDbException' with message 'CDbConnection failed to open the DB connection.' in /var/www/YII/yii-1.1.8.r3324/framework/db/CDbConnection.php:370

Below is the db configuration in YII

   'db'=>array(
                    'connectionString'      => 'mysql:host=xxxx;dbname=PortalDB;port=4040;',
                    'emulatePrepare'        => true,
                    'username'              => 'root',
                    'password'              => 'mysql',
                    'charset'               => 'utf8',
                    'queryCachingDuration'  => 300,
                    'enableParamLogging'    => true
            ),
            'db2'=>array(

                'class'                 => 'CDbConnection',
                'connectionString'      => 'mysql:host=xxxx;dbname=PortalDB;port=4040;',//devdbserver.c27hiz0xxzr5.us-east-1.rds.amazonaws.com
                'emulatePrepare'        => true,
                'username'              => 'root',
                'password'              => 'mysql',
                'charset'               => 'utf8',
                'queryCachingDuration'  => 300,
                'enableParamLogging'    => true
            ),