question 1: Not sure, but if you drag the progress bar on media player back and forth, you may got this unsynchronized problem. If so, try to let it play continually or pause it first and start again. There is also a chance that the original version had this problem also, I downloaded mine which is 3 cds. One of them has the jumping sound, I tried download twice but still can't solve this problem.
question2: I want to know too.