3D FlipBook - Error: Setting up fake worker failed:

I am getting this error on my website it was all working fine but now get this error when loading a page.... can you help?

Error: Setting up fake worker failed: "Cannot load script at: http://theheritageschool.net/library/wp-content/plugins/real3d-flipbook/js/pdf.worker.min.js?ver=3.8.2".