TypeError: api.nextSlide is not a function

I’m getting the error “TypeError: api.nextSlide is not a function”.
The first slide loads, but will not auto play and I cannot use the navigation arrow to get to the next slide either.

Images are being loaded from a nextGen gallery. Any suggestions on how to fix this?

http://www.imageworkshop.com/

https://wordpress.org/plugins/wp-supersized/