yii: Property "CWebUser.clientScript" is not defined

Hi iam newbie to yii framework. And iam getting this error after submitting the login details.

error

C:\wamp\www\yii\framework\web\auth\CWebUser.php(154)

152| $this->setState($name,$value);
153| else    
154| parent::__set($name,$value);
155| }

and in STACKTRACE

C:\wamp\www\yiiapp1\protected\models\LoginForm.php(71): CModule->__get("user")

70| $duration=$this->rememberMe ? 3600*24*30 : 0; // 30 days
71|             Yii::app()->user->login($this->_identity,$duration);
72|             return true;

THIS IS MY USER.PHP FILE

class user extends CActiveRecord
{
         public function validatePassword($password)
    {
        return CPasswordHelper::verifyPassword($password,$this->password);
    }

    public function hashPassword($password)
    {
        return CPasswordHelper::hashPassword($password);
    }



        public static function model($className=__CLASS__)
        {
                return parent::model($className);
        }


        public function tableName()
        {
                return 'user';
        }

        public function rules()
        {

                return array(
                        array('', 'safe', 'on'=>'search'),
                );
        }

        public function relations()
        {

                return array(
                );
        }


        public function attributeLabels()
        {
                return array(
                );
        }


        public function search()
        {


                $criteria=new CDbCriteria;

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

LOGINFORM

class LoginForm extends CFormModel
{
        public $username;
        public $password;
        public $rememberMe;
        private $_identity;


        public function rules()
        {
                return array(
                        // username and password are required
                        array('username, password', 'required'),
                        // rememberMe needs to be a boolean
                        array('rememberMe', 'boolean'),
                        // password needs to be authenticated
                        array('password', 'authenticate'),
                );
        }


        public function attributeLabels()
        {
                return array(
                        'rememberMe'=>'Remember me next time',
                );
        }

        public function authenticate($attribute,$params)
        {
                if(!$this->hasErrors())
                {
                        $this->_identity=new UserIdentity($this->username,$this->password);
                        if(!$this->_identity->authenticate())
                                $this->addError('password','Incorrect username or password.');
                }
        }


public function login($identity,$duration)
        {
                if($this->_identity===null)
                {
                        $this->_identity=new UserIdentity($this->username,$this->password);
                        $this->_identity->authenticate();
                }
                if($this->_identity->errorCode===UserIdentity::ERROR_NONE)
                {

                        $duration=$this->rememberMe ? 3600*24*30 : 0; // 30 days
                        Yii::app()->user->login($this->_identity,$duration);// --> HERE THE STACKTRACE SHOWING THE ERROR
                        return true;
                }
                else
                        return false;
        }
}