You want the Contact Form 7 response message when you push submit in a popup colorbox window? This small plugin does just that.
This plugin requires Contact Form 7 and Lightbox Plus Colorbox. Install them first and then try active it again.
You have an older version of Lightbox Plus Colorbox. Updating it should fix the problem.
This plugin doesn't put an entire contact form inside a colorbox popup but just the response message when you click the Submit Button.