I have the same soundcard (AC97) that came integrated in my motherboard (Asrock K7VM2). My mobo's south bridge is VIA 8235.
The card works perfectly with the kernel OSS drivers (custom 2.6.7 kernel), but without microphone support. With ALSA, it works ok and has complete mic support.
Perhaps you should try checking the /dev/dsp symlink's permissions.
Also it might be that the sound modules are not loaded (check 'lsmod' on the console).
Hope this helps.