Access violation error

I complied an IE book.
The source file was an html file with a simple javascript quiz.
The book loads ok, showing the page with the test questions. However, when I select the answers and click on “check results”, I get the following error:

Access violation address 0071C2AD in module “mybook.exe”. Read address violation 0000000.

I tested the html page on Chrome (works ok), Firefox (works ok), and IE (works ok, although it says the activex or javascript was blocked, and I have to choose “allow javascript to run” first in order to make it work.

Looks like a multithreading problem. Try to play with these two options: