Preview in browser?

I'll echo (echo... echo...) Ron & Joe: Publish for Web to your local drive, and test that. 

BTW, I find this helpful for quality-assurance testing/editing. I step through the published version of the course. When I find something that needs correcting (e.g., typos!), I fix it immediately in the .story file. Then I keep stepping through the published version to ensure the entire thing works as expected. That includes stepping through it backwards, to check that PREV goes where it should, and slides behave as expected on revisiting. Depending on the number of complexity of corrections, I'll repeat that process. 

Why? Because (I speak from experience here): some things that work when you preview a given slide don't work going forward or backward through the overall course.