I had this problem once. I thought I had put the three cables to the audigy in the right order but I hadn't. My card has gold plated inputs with no color coding. Try switching the plugs around when someone is listening. And also check the front/rear fader ofcourse
A great resource is
news://news.creative.com/
It doesn't matter if you use the creative mixer or the speaker setup in control panel, they do the same and should be set to 5.1 if that's what you want.