Membership: upgrading plugin broke plugin: White Screen of Death and Coupons

Hi - please prioritize. My site is inoperable after upgrading.

site: http://www.speaksheets.com
WP: 3.5.1
Membership: 3.4.3.1
Affiliate: 3.1.2

When I reach the registration page during the subscription process, I get a white screen of death. It DOES create the WP user account. I can reload the page to then get the Subscribe button and proceed.
http://www.speaksheets.com/register/?action=registeruser&subscription=1

Thought it could have been a cache plugin (W3) - disabled it, did not help. Defaulting to Twenty Twelve theme (from Thesis) does not work.

Also, Coupons are not working. I created a coupon, got the message "Coupon added", but nothing shows up on the coupon admin screen. When I attempt to use the coupon, I get this message: "The Coupon code is invalid."

thanks
tyler