Spambots suddenly getting past reCaptcha in phpbb

reCaptcha was working fine and now suddenly this past week I'm getting a ton of spambots trying to create accounts. Any ideas why? http://bit.ly/1wZRl3Q -- 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.