You are welcome to take them ahead of time. But credit will not be given if the deadline is missed. I hope and expect these problems with WebCT to be corrected but they were a severe problem this past semester. These will be taken online using WebCT, just like the online quizzes. They are useful and interesting.
Communication is important.
Keeping current with the course material is vital. With only two exams, it will be very easy to get so far behind that you can not possibly catch up. Don't do that to yourself. I have set up a bulletin board to make communication easy. There you can post a question and other students can comment on it and I will try to answer it, too.