Ok, I've got a potential fix for you.  If you would be so kind as to download the file at this link: https://www.dropbox.com/s/s8n4ca8h8xt0fu8/JigsawSvgGenerator.cs?dl=0

This is a replacement for the JigsawSvgGenerator script that you can find in "Jigsaw puzzle package -> Jigsaw puzzle generation -> Scripts -> Jigsaw puzzle generation system".  If you replace the script there with this new one and then try again hopefully you should see that the puzzle generates successfully this time.

Let me know if that works and if it does I will issue the fix to the package here so that no-one else has the same problems! 

That's fantastic, and a big relief!  Thank you for your help with diagnosing the problem.  It was a bug that could potentially affect many other people so I really appreciate you providing the information that was essential for revealing what the source of the problem was.  I'll add the fix to the package shortly.

Yes, of course.  The trick is to use a render texture for the jigsaw puzzle texture, rather than an image.  You then set up an area out of sight of the main camera where you set up another camera pointing at the animated scene (it could even be 3D).  The output of that second camera gets sent to the render texture, so that whatever happens in the animated scene will show up on the jigsaw.  I hope that helps point you in the right direction.