I don\'t know about your OS or what other devices you have, but in the case you have a modem with voice (often the case with 56k modems), or another sound chip on your motherboard, disable them. You can do that from the device manager under WinXP, for instance.
I had this problem once with another program because of a modem, on WinMe I think. Just disabling the modem voice support solved it. What happened is that the program was selecting the wrong device, even if the SBLive was the default one in Windows.
I suppose you have tried to install the drivers from CreativeLabs ? If the tip above doesn\'t work, it might be worth it.
* muttering something evil about Dell-modified drivers *