The problems that you, and others, are experiencing are browser-related (see security settings). There’s no way my servers are having a problem with files ranging from 10K to 100K. The whole thing weighs in at less than 1MB uncompressed.
I think the “crashing” that people are experiencing is as I explained underneath the See Test Results button. For some reason, in Firefox, you may have to move the scrollbar after clicking the See Test Results button. That’s the only issue I’ve ever experienced. Also, I’ve had zero problems in IE7.
If the problems you are having fall outside of what I’ve described, please give me more details (screenshot of it “hanging” if possible, error messages) because I would like it to work for as many people as possible.
BTW, I used the freeware app called QuizFaber to produce most of the test.
Glad you like it, sorry for any issues you may be experiencing.