I'm 100% sure it was not the mixer. I found something on the ubuntu forums about exactly what you said. They told me to uninstall the alsa and reinstall, but when I did that it screwd up gnome and UU1.5. So I ended up having to reinstall UU again

So dissapointing that they can't care to fix this bug as you said. I'm also getting a IO-APIC bug when UU starts up. Although I don't think it seriously affect anything on my laptop, I think it's a really anoying bug and I would like to get rid of it. I've tried adding "noapic" to the kernel line in grub menu.lst but no success. When I do that the systems hangs forever and never boots. If anyone has a solution for this, I'd really appreciate it.