One of those pop-up error messages that leave me baffled.

[Robert Stevenson]

In Chrome students are getting: "Uncaught Type Error. Cannot read property 'current position' of undefined (line number 1239). If anyone could share some wisdom on what might be the issue here I'd sure appreciate it. Curious as well that no one seems to be able to get over 40%. This is an older updated TB using catalog question objects.

[Clifton]

These error messages come down to objects that have been deleted but are still referenced on the page(s). You may be able to locate them using the validate actions item in the Tools menu at author level. This may or may not work. Otherwise, for the problem pages you will have to inspect each object to find out if something is referenced that is no longer present on the page.

Regarding scoring, this is basically a similar issue. If pages have been added/removed and book is somehow out of sync, then not all the questions are being scored when the student reaches the summary page. Sometimes this can be fixed by rebuilding the score mechanism on the summary page. Otherwise, you may have to check the properties of each question to make sure they are flagged to be scored and that they are reporting their score values correctly.

There is no magic bullet for troubleshooting this, but you just need to patiently verify each object and question to make sure it is not doing something illegal in the exported content.