Thanks for the info. I just got into the site. The issue looks to be how JFBConnect tries to modify the output to add our contents. Your jgrid extension is using a ton of Javascript, and one of the statements is confusing JFBConnect.
What I'd recommend is a bit of code that will disable the JFBCSystem plugin in that section. It's what you asked for originally, but not something we have as an option (or plan to add) within JFBConnect. To do so, edit the /plugins/system/jfbcsystem/jfbcsystem.php file. Around line 25, you'll see:
function __construct(& $subject, $config)
{
Update that code so it looks like:
function __construct(& $subject, $config)
{
if (JRequest::getInt('Itemid') == 1959)
return;
1959 is the Menu Item id for your jgrid item, so that should get you going.
Let us know how that goes. We'll look into updating our code to properly detect situations like you're running into and work better so that you won't need that code.
Thanks,
Alex