captcha problem in backend

hi there

i added captcha in my logins(backend and frontend)

in the frontend there is no problem, but in the backend, the captcha image not load but validation for captcha works.

what should i do?

i think its like a bug etc…

found a solution here : http://www.yiiframework.com/forum/index.php/topic/60678-captcha-in-the-backend-not-showing/page__gopid__275479#entry275479

but cant refresh the captcha by clicking

how to do that?