Error message with reCAPTCHA for PHP

The form validation appears to happen, however, I get the following error:"Name of form element recaptcha_challenge_field cannot be longer than 20 characters".this is the page with the form in question (http://bit.ly/1qvbcVi)Could someone help me?Thank you. -- You received this message because you are subscribed to the Google Groups "reCAPTCHA" group. To unsubscribe from this group and stop receiving emails from it, send an email to recaptcha+unsubscribe@googlegroups.com. To post to this group, send email to recaptcha@googlegroups.com. Visit this group at http://bit.ly/1dkFnYd. For more options, visit http://bit.ly/P65DvS.