your kernel seems to be missing the ac97_codec.o module.
(Re)install this module and your sound should work fine.
If you don't want to recompile your kernel, I suggest to install
also the driver called
"Intel ICH (i8xx), SiS 7012, NVidia nForce Audio or AMD 768/811x"
(kernel config-option CONFIG_SOUND_ICH) should work fine and also depends/provides on/an ac97_codec.o. If you are playing Quake3 you have to use this driver (Quake3 crashes with nvaudio.o).
good luck ...