astsure on "Contact Form 7 and WP Super Cache can't work together?"

When I turn on WP Super Cache, people are unable to submit forms via the Contact Form 7. They get the red error message. Are these two not compatible?
I am trying to make our website run faster so I turned on the caching, but I will have to turn it off if it doesn't work with Contact Form 7.
Any suggestions?
Here is the site.

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