Thanks, Caliderumba, for responding. Good suggestions. Here's what we'd say in general for an issue like mentioned:
If you're seeing a blank white page, that means there's a PHP error being thrown on the page for some reason. Please go to the Global Configuration area and set "Error Reporting" to 'maximum'. That should show a real error message on the blank page that we can use to diagnose what's going wrong.
We haven't heard of this issue before, but we'll gladly help narrow things down. There's likely a missing PHP library on your site or something like that.
Finally, JFBConnect works only on Joomla 2.5.5+. If you are running on Joomla 1.6.x, 1.7.x or 2.5.0-2.5.4, that could also be the problem. You'd need to upgrade Joomla to get JFBConnect to work. However, 2.5.5 is more than a year and a half old by now, so you shouldn't be using it anyways...
I hope that helps,
Alex