[Plugin: Easy Contact Forms] reCaptcha returns incorrect answer even when correct

Hi Im testing the plugin to replace another plugin Im using but have came across this problem where recaptcha is coming back as invalid even for correct answers. I have recaptcha enabled for comments & registration and that works fine. How can I check whats the problem?

The form is located here: http://www.kingston23.com/activity

Thanks

http://wordpress.org/extend/plugins/easy-contact-forms/