New recaptcha Not working

Have recaptcha on one site working fine. Installed the New reCaptcha on main site in Joomla 2.5, added the site key and secret key, all I get is the message"Captcha plugin not set or not found. Please contact a site administrator" Not sure about the addition line which includes "https://www.google.com/recaptcha/api/siteverify" Even registered as a new site with other key codes and still will not work.
Can anyone help please?