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 Simple Colorbox or 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. If not, try another plugin that has colorbox js library like : Simple Colorbox(make sure to deactivate Lightbox Plus Colorbox).
This plugin doesn't put an entire contact form inside a colorbox popup but just the response message when you click the Submit Button.