Hi all,
I just tried activating the WATS plugin (WordPress Advanced Ticketing System) and my entire admin area went blank. After some troubleshooting, I determined that WATS and Gravity Forms have some kind of conflict. Read more here:
http://wordpress.org/support/topic/389551?replies=1
I wanted to alert you in case it was something in GF causing it, but I suspect it's the other plugin;)