Adding Captcha Validator into validator List

Hi,

I am using capcha only one of my action. That a reason I add the validator into beforeValidation. The problem is validation always return "Verify Cod is incorrect" error message

Any idea. Thanks

public function beforeValidate() {

            if(Yii::app()->controller->action->id=='forgetPassword'){

                $validator = new CCaptchaValidator();

                $validator->caseSensitive=false;

                $validator->captchaAction='captcha';

                $validator->allowEmpty=false;

                $validator->attributes = array('verifyCode');

                $validator->skipOnError=false;

                //$validator->on=array('create'=>'create');

                $this->validatorList->add($validator);

            }

            return parent::beforeValidate();

        }