Cthumbcreator

hi i have followed CThumbCreator extension

and have put CThumbCreator.php file in protected->extensions->CThumbCreator.php and in main.php i have written this :

‘components’=>array(

	'user'=>array(


		// enable cookie-based authentication


		'allowAutoLogin'=>true,


	),


    'simple_image'=>array(


        'class' => 'application.extensions.CSimpleImage',


    ),


    'components'=>array(


        'thumb'=>array(


            'class'=>'application.extensions.CThumbCreator',


            'width' => 160,


            'height'=> 160,


             'prefix'=>'img',


            'defaultName' => "mythumb",


            'directory' => "uploads/small"


        )


    ),

and in MyController file i have used this code:

 public function actionAddDirectors()


{


    $modelDirectors = new BoardOfDirectors;


    $imagetime=time();


    if(isset($_POST['BoardOfDirectors']))


    {   $modelDirectors->attributes= $_POST['BoardOfDirectors'];


        define('UPLOADED_IMAGE_DESTINATION', './uploads/');


        //define('NORMAL_IMAGE_DESTINATION', './uploads/normal/');


        define('THUMBNAIL_IMAGE_DESTINATION', './uploads/small/');


        define('THUMBNAIL_IMAGE_MAX_WIDTH',160);


        define('THUMBNAIL_IMAGE_MAX_HEIGHT',160);


        $modelDirectors->image    = CUploadedFile::getInstanceByName("image");


        $modelDirectors->image->saveAs(UPLOADED_IMAGE_DESTINATION.$imagetime.CUploadedFile::getInstanceByName("image"));


        $type=$modelDirectors->image->extensionName;


        $thumbNew = Yii::app()->thumb;


        $thumbNew->image = CUploadedFile::getInstanceByName("image");


        $thumbNew->width = 160;


        $thumbNew->height = 160;





        $thumbNew->createThumb();


        $thumbNew->directory = THUMBNAIL_IMAGE_DESTINATION;


        $thumbNew->save();








        $modelDirectors->name     = $_POST['BoardOfDirectors']['name'];


        $modelDirectors->position = $_POST['BoardOfDirectors']['position'];

}

but i am getting exception in this LOC : $thumbNew = Yii::app()->thumb;

The Exception is : CException

Property "CWebApplication.thumb" is not defined.

D:\xampp\htdocs\AlFerdousYII\protected\controllers\BoardOfDirectorsController.php(175): CModule->__get("thumb")

170 define(‘THUMBNAIL_IMAGE_MAX_WIDTH’,160);

171 define(‘THUMBNAIL_IMAGE_MAX_HEIGHT’,160);

172 $modelDirectors->image = CUploadedFile::getInstanceByName("image");

173 $modelDirectors->image->saveAs(UPLOADED_IMAGE_DESTINATION.$imagetime.CUploadedFile::getInstanceByName("image"));

174 $type=$modelDirectors->image->extensionName;

175 $thumbNew = Yii::app()->thumb;

176 $thumbNew->image = CUploadedFile::getInstanceByName("image");