Hi there. I tried searchin help at the #Ubuntu IRC, but didn't get any help, hence I came here.
So down to the problem!
When I change the volume under ~20% it goes mute.
Here is le badly drawn picture of my desktop
At the top right you can see the volume editor. The current volume level that you can see in this pic is mute on my computer. Whenever the I drag the pin below that point, it goes mute.
I'm not really sure how to explain this easily, but if you have any questions regarding the bug / my choise of words please feel free to ask.
Your help means alot - thank you!