Captcha produces text "Object id .."

Yii 1.1 General Discussion
1

I am using captcha on a form. It works but produces extra text like "Object id 89".

How can I remove this additional text. I am using 1.1.10 and here is the model rule for it

array(‘verifyCode’, ‘captcha’, ‘allowEmpty’=>!CCaptcha::checkRequirements()),