Napolean,
You don't know me (I am new to this board), but I just re-bought WC3 and I had the same problem, and I think that I have the 64V Soundblaster as well. When I configured it using the SoundBlaster AWE and 16, I had the same problem, the movie would stop.
However, if you set the soundcard to just the SoundBlaster Compatible choice(the first one), it may work. It did for me, but what do I know....