I'm having the same problem. When I run the hardware test in the voice tab of audio properties I get the directplay error 0x80040154 followed by the error message that windows could not execute DPVSETUP.EXE
My mic doesn't work because of this. Is there an error in the dll or what? I have dx9.0c, windows XP, an asus a7n8x2 mobo with onboard sound. I've had the same problem with the onboard ac97 sound disabled using a pci soundblaster live 5.1 as well.
latest drivers, uninstalled, reinstalled, yadayadayada