Slides not loading

I have the “Slideshow” plugin by Stefan Boonstra and it has been working perfectly until today. I have the shortcode [slideshow_deploy id=’428′]
on the page and it is in a widget for the sidebar – none of that has changed. I have read many other threads in the forum but don’t understand them and how they would apply to my site. I tried clearing the cache and the history and deactivating and reactivating the plug but with no improvement.

My site is http://whchurchofchrist.org.

I would appreciate any help I can get to resolve this issue. Thanks.