I just installed Ubuntu 5.04 and all of the system sounds are fine, but I installed Tux Racer to make sure my graphics card was working and the game runs great, but there's no sound. And when I start the game from the console I get this error:
I have an nForce2 motherboard and I am running audio off of that.

Thanks.

Without sitting in front of my ubuntu system and grabbing tux racer, I would say this issue has to do with either esd or oss support (probably the former).

I've seen problems similar to yours when a application is trying to use Alsa for sound but esd is running. Esd interferes and prevents the application from getting to the device. Or, it could be the application is set to use the deprecated oss sound drivers and you don't have alsa-oss support loaded in.

Those are my two guesses.

Oh, another thing, if the app is using libao there is a file that sets the default libao device: /etc/libao.conf. I believe it is set for esd in ubuntu. Since I don't run gnome and thus no esd I have to set this to alsa instead.