Does pay by like work with Total Cache

Pay by Like is not working for me. I'm using Jetpack and Total Cache. I'm able to see the like wall and can, for example, post to twitter. However the paywall does not open and the content is not revealed.

I opened the page in firebug and see the following error:

ReferenceError: FB is not defined

in http://cdn.eventenrichment.org/wp-content/plugins/pay-with-a-like/js/pay-with-a-like.js?ver=1.1.5

Please advise.

thx!