Uncaught TypeError

I’m having trouble with CSS animations breaking on a page that is using AWB. It is sporadic though. Sometimes it works, and other times it doesn’t. When it doesn’t I can inspect the page and see this error:

jarallax.js:529 Uncaught TypeError: Cannot read property 'style' of undefined
    at jarallax.js:529
    at Array.forEach (<anonymous>)
    at j.value (jarallax.js:528)
    at j.value (jarallax.js:996)
    at j.t.onScroll (jarallax-video.min.js?ver=1.11.0:6)
    at HTMLDivElement.<anonymous> (awb.min.js?ver=1.6.0:5)
    at Function.each (jquery.js:2)
    at a.fn.init.each (jquery.js:2)
    at awb.min.js?ver=1.6.0:5
    at Array.forEach (<anonymous>)

Any idea what this means or how to fix?

The page I need help with: [log in to see the link]