The quiz freezes

Hi,
I will post my questions here since I did not get any answers with my email. You came to see the setting but I did not get any news, so, my questions are:
1- The quizzes are long quizzes and they freeze erery 10 to 15 questions so, we have to start from beginning every time it happens. Is it because the JPEG inserted are to heavy or we need to have quizzes with a certain amout of questions only ?
2- If a customer buy 2 trainings, when they press (Save as draft), they automatically have access to all the quizzes available ?

We payed the person you referred us for a course and this problem wasen't solved !!

Thanks again,

Sylvie