Contact Form 7 is conflicting with captcha plugin

Hi,
I’m using contact form 7 and it works perfectly until I installed Really Simple Captcha. Now when submitting the form, it just keeps spinning and no validation errors come up. It forever spins. I tried deactivating all plugins and found that it’s actually the Captcha plugin causing the issue. Do you know how I can fix this? Is it because I’m running it off my local server? The captcha appears.

http://wordpress.org/extend/plugins/contact-form-7/