After completely uninstalling the FEC module, I still couldn't get past the "login" page. Further searching brought me to: http://www.zen-cart.com/forum/showth...78#post1115678

To anyone else running into a "blank page" problem - check the /cache/ folder for a myDebug file, that should lead you in the direction of the problem.

Turns out it wasn't FEC's fault. Oh well - time to reinstall.