Hello,
I just updated my wp install from 4.4 to 4.5 then updated the file manager plugin from 2.0.1 to 2.2.4 only to return to the beloved WSOD and returned a 500 error.
After deactivating/downgrading the plugin the website loaded correctly.
Thanks for developing this plugin, it's really useful for the kiddies who don't know how to FTP. Keep up the good work!