Could not open Socket error

[Mia Harper]

Hi

I have installed the ReCaptcha PHP library and am having trouble getting the included example scripts to work. The captcha is displayed but when the form is submitted, the only response is 'Could not open socket'

http://www.squaregroup.co.uk/includes/recaptcha-php-1.11/example-captcha.php

Is anybody able to advise me on the best way to troubleshoot this problem? The server is sitting behind a load balancer.

Thank you so much in advance of any help!