Try a different BIOS image, yours may be corrupt and causing the emulator to crash.
Also there are probably more recent drivers to be found for your Voodoo card than the ones you're using, there's a whole community out there doing hacked drivers.
I don't have any first hand knowledge with those, but I'm sure there's someone around here who can point you in the right direction. Every forum has at least one 3dfx enthusiast.. ;D