Help With Filters Please My Cgridview Does Not Filter

Hi All

Can some one please help me with my filters, they do not seem to be getting data from the database.
View

$this->widget('zii.widgets.grid.CGridView', array(
    'id'=>'user-grid',
    'dataProvider'=>$model->search(),
    'filter'=>$model,
    'enablePagination'=>true,
	'pager'=>array(
        'maxButtonCount'=>'7',
    ),
    'columns'=>array(
		array(
			'name'=>'bt_number',
			'type'=>'raw',
			'value'=>$model->bt_number,

		),
		array(
			'name'=>'date_time',
			'type'=>'raw',
			'value'=>$model->date_time,
		),
                array(
			'name'=>'broker',
			'type'=>'raw',
                        'value'=>$model->broker,
			'filter'=>Yii::app()->params['brokers'],
			
		),
		array(
			'class'=>'CButtonColumn',
			'template'=>'{view}{update}'
		),
    )
));

Model

public function search()
	{
		// Warning: Please modify the following code to remove attributes that
		// should not be searched.

		echo "booker ".$this->broker;// exit;
               //above only displays booker there is nothing in $this->broker
		
		$criteria=new CDbCriteria;

		$criteria->compare('bt_number',$this->bt_number);
		$criteria->compare('sign',$this->sign,true);
		$criteria->compare('fm_buys',$this->fm_buys,true);
		$criteria->compare('fm_buys_amt',$this->fm_buys_amt,true);
		$criteria->compare('against',$this->against,true);
		$criteria->compare('bt_sett_date',$this->bt_sett_date,true);
		$criteria->compare('bt_order_type',$this->bt_order_type,true);
		$criteria->compare('date_time',$this->date_time,true);
		$criteria->compare('dealer',$this->dealer,true);
		$criteria->compare('rate',$this->rate,true);
		$criteria->compare('broker',$this->broker,true);
		$criteria->compare('recapped',$this->recapped,true);
		$criteria->compare('settled',$this->settled,true);
		$criteria->compare('sett_date',$this->sett_date,true);

		return new CActiveDataProvider($this, array(
			'criteria'=>$criteria,
		));
	}

Controller

public function actionIndex()
	{
		$model=new BrokerTrades('search');
		$model->unsetAttributes();  // clear any default values
		if(isset($_GET['BrokerTrades']))
			$model->attributes=$_GET['BrokerTrades'];
		
		print_r($_GET)	;
		$this->render('index',array(
			'model'=>$model,
		));
	}

I can not see why this filter is not work please help.