captcha in comments

I cannt see the two words in the captcha commet.

Where are the two words?

Thanks

PD : see
http://demo.gavick.com/joomla16/jun2011 ... ial-market
and try post a comment

Captcha and comments are disabled on our demo site, this is why you don't see proper field.

Captcha and comments are disabled on our demo site, this is why you don't see proper field.

On my site its disabled. How to enable it??