White Screen with System - JFBCSystem

ckka,
A white screen error is likely caused by one of the following 2 server configuration issues:
1) You are not using PHP 5.x
2) You do not have the cURL extension for PHP enabled. This is by default enabled within PHP, but some server hosts disable it.

JFBConnect requires both of the above. If you are unsure of the problem, you can go to the Global Configuration area of Joomla and set "Error Reporting" to maximum. When you visit the Overview page in the admin area, a text error should appear that describes the problem. If you get one, please post it and we can help you narrow down the issue further.

In the upcoming v4.2 release, we'll have better error reporting to call out these problems, but both of the above will still be required.

Hope that helps,
Alex