What does this "Exception" mean?

Nice! 

Usually (in my experience) errors like this mean there is one slide that it does not like, however...in usual "exception convention" there's no way normal human beings know how to track down which slide.

I usually try and break the original into pieces, and import bit at a time to track down things like this.

Sorry I cannot offer a more useful/in-depth set of options here.

Bruce

Hi Joyce

Yep Bruce is right.

I usually get this error when trying to import ppt-files that contains hidden slides

Geert

It's likely breaking on a slide that contains a quizmaker object. Bruce, as usual, comes bearing great advice. 

I started out my young career as an electronics technician in the military. One helpful strategy for troubleshooting systems of any level of complexity or scale is "half-stepping". I use this method when I run into errors and issues like yours above. 

When importing your file, you can select which slides to import. You might try strategically deselecting half of the slides. If the problem goes away, you know the issue lives in the half you didn't import. Strategically select half again of the remaining slides, and so on, until the problem is isolated.

Based on the error above, I'd wager the problem is a slide that contains a Quizmaker slide. With this in mind, if you only have 2 quizmaker slides, you could try to exclude each of these from the import process. If the problem goes away, add each of these back in one at a time until the problem appears.

...also known in IT as a "...binary split...", and in mathematics as a "divide and conquer algorithm"

Bruce

...and now back to our normal programming.

Thanks for the help.  I think most everything loaded, I'll go back and take a look at how the quiz came out.  I'd rather not rebuild it, but if I must, I must.