Ensure that you don't have any other sound modules loaded. Run an 'lsmod' to see what modules are currently loaded in your system. As well, if your distributions comes with a ready-made kernel, it may have sound compiled directly into the kernel (which i doubt).
If you find any sound modules there, say i810_audio, remove them from the running kernel with "rmmod -r i810_audio", and then insert the nvaudio drivers with "modprobe -v nvaudio".
But, it does sound to me like there's already drivers loaded, so, run through your lsmod and make sure.