Progression from slide to slide freezes in published course

Hi Everybody,

I have found a problem when testing a new course.

Within Articulate Storyline 2, the whole course previews without problems and everything seems to work.

However, in the published course (web ouput), the playback gets stuck at a certain point in the quiz section.

It freezes up and then goes to a black screen and progresses no further no matter how long I wait.
It does the same every time.
It does the same whether I am looking at a local copy on my laptop, or a copy on the webserver.
It happens at a point where the question style/scene switch from T/F to Drag and Drop formats.

I cannot see any reason in the project why this should be the case – all the triggers and connections are correct as far as I can see, and the preview works just fine.

I have tried publishing again to see if the problem occurred as a corruption during the publication process. But it occurs again in second and third published versions.

Any thoughts? Have you seen this before?