This is not an uncommon problem. I doubt I'll be able to help, but I solved the problem (with Asus CUSL2) by disabling the 2nd USB port in my device manager.
I would suggest that you consult your mobo's manual, and move the card to a slot that does not share an IRQ, but it sounds like you've already done this.
For W9x version O/S, I always disable DOS legacy support in the dev mgr.
If worse come to worse, you could always try Creative sppt, or sel the card for a Turtle Beach, which many seem to find less problematic.
I have the SB Live Value.
On another note, I have no experience with Via, but have not heard many good things about their chipsets .. other than they're getting better.
I just noticed that you're the 100th registered user .. I should probably give you some kind of door prize.