volume hot keys in Crunchbang don't work

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http://unix.stackexchange.com – I've spent 2 hours on this and still can't figure this out. It's driving me insane. Please save my sanity. When I press mute, the pnmixer control in the top right shows that I've pressed mute, but the sound is not muted. A graphic also appears on my screen with a volume bar to show that the volume has been muted. When I press mute again, the pnmixer control shows that I have pressed the key, and three graphics appear on my screen in a row to show that I've pressed it. This doesn't make sense. No change in sound. With the volume up and down keys, the graphic changes accordingly but agai (HowTos)