No problem about the subscription. If you would, please have your wife post to this thread, or create new ones, so we know who we're supporting. It helps. We can add the subscription to your account too, once we know who's account to associate it with.
As for the warning you're seeing, if you edit the jfbsystem.php file you've pasted above, at that line, simply change the code to the following, and you'll be good to go:
if (preg_match('/\<body.*?\>/', $body, $matches))
{
$newBody = str_replace($matches[0], $matches[0] . $fbApiJs, $body);
JResponse::setBody($newBody);
}
That will get rid of the warning. Additionally, you can turn off error reporting in the Joomla configuration error as warnings are not 'critical' problems. This issue has been fixed in the 3.2 release, and you shouldn't see it once that's released as well.
Hope this helps, and good luck!