reCaptcha show “input error: invalid referer

I have registered an account on http://bit.ly/1mE8QBI for my website, while I'm developing on my localhost for guestbook captcha, it works fine, but whenever I try to open the page from another machine in my local network it shows "input error: invalid referer" error message! I have fill Public key and private key with correctly Please help -- 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.