Hi,
I have the same problem. A programmer was working on some Theme customizations remotely so I de-activated the BPS Pro to allow changes. I logged in and was having problems backing-up with Ultradraft PRO so I deactivated it and activated BPS and now I get a white screen.
I tried renaming the plugin folder, I already deleted the BPS folder and Ultradraft plugin folder and even the .htaccess inside the plugins folder, that was putting a firewall.
Still nothing… white screen front and back.
HELP!