Today I had a few complaints from users not being able to download PDFs from one of the sites I manage. Users were not able to get beyond the registration page which kept hanging due to an error on reCAPTCHA. The error caused the $rep->is_valid to return null. I am not sure if the problem was in validating the reCaptcha words or if it was in sending a response back. The fix was pointed out by reCAPTCHA support in a Google group. I just want to make it more public here.
Update your current recaptchalib.php with the one from http://code.google.com/p/recaptcha/downloads/detail?name=recaptcha-php-1.10.zip
