That line disables:
* Using a different template when inside your Canvas (probably not important, as you might not have been using it)
* Using a different template when inside your Page Tab
* Facebook Page Tab "Reveal Pages"
* Facebook Request redirections (Require Canvas support) - May or may not be used
* Probably some other minor stuff
For now, obviously, you're probably good. It's definitely good that we did narrow down that the issue is in our Canvas integration stuff. The thing we'd need to do now is simply refine the IF statement that didn't work above to target the PhotoBattle comments more specifically. If the above are issues (you plan to use those features), we can help more. If not, I'd recommend just leaving it is for now until you want to use those other features in JFBConnect.
No problem for the support.. it's what we're here for!
Alex