[Plugin: Contact Form 7] Ajax effect for validation not working when we use lightbox?

I used CF7 in a page here – http://stg.qontext.com/next-steps/
and the same form as well (scroll down to the end of the page)via a lightbox effect – http://stg.qontext.com/products/overview/social-collaboration-platform/

CF7 works as expected in the first instance, but the ajax effect for form validation does not work in the second instance. Can you help me figure out what the reason may be?