Comments Plus Breaks Gravity Forms

Hi there, pretty much as the title says, I have a form on one of my blogs and a user reported the form to be missing, I suspected the culprit might be a recently enabled plugin so I disabled comments plus and bingo, gravity forms was back.

Here was the post in question:
http://drummersdatabase.com/blog/2012/09/ad-snare-competition-voting-round-3/#comment-87

Any ideas what might have happened?

Thanks folks!