I just installed Jetpack comments and I’m not getting that error. My site is still in development and is here: http://www.hbmintegrated.com/new_wp_site/
What I like about the Jetpack version too is that it doesn’t require the user to include http:// in the commenter’s website url, whereas the default one does. I think many commenters will be confused by this, as the error simply reads “Please enter a URL”, rather than “please include http:// in your url”. I tested this on your site and got the same confusing message.
Hope you find the feedback helpful…