Black screen when loggin on with facebook

First, make sure that you only have the JFBCProfile plugins enabled for extensions that you actually have. So, if you don't have Community Builder installed, don't enable the JFBCProfile - Community Builder plugin.

If that doesn't help, the go to the Global Configuration of Joomla and set Error Reporting to "Maximum". Then, try to login again and let us know if there are any error messages that appear. That will help narrow down what is causing the problem.

Thanks,
Alex