I guess I'm not seeing something from the demo, everytime I press start, I get a message - "You must apply the prose-paint to the painting first!" I watched th

I guess I'm not seeing something from the demo, everytime I press start, I get a message - "You must apply the prose-paint to the painting first!" I watched the demo from the tweet above and I think I am doing it correctly. Edit - I am using an old version of chrome - which was the problem.