Yup it's a common problem!
Turn down hardware acceleration for the sound, the easiest way if probably
via the dxdiag tool, and make sure you have the latest drivers from
Creative, although I'm not convinced the drivers made any difference on
mine.
I had the same problem with a SBLive 5.1 & win2k, and it's okay (still
crackles a bit) with the hardware acceleration on 'basic', one up from none.
Do a google search on this group, you'll find plenty of other suggestions.
Malc.