DVD 4.0 Sound always on

I love the new Knoppix DVD but have a problem I haven't encountered with any other distro of Linux - previous Knoppix included:

I have an old ATI TV Card in my computer and when my machine boots with Knoppix, it "senses" the card and immediate begins playing TV sound. If I try to load the TV software xawtv, the software works flawlessly - as good as the MS software that was made for the card. However, if I close the program, the sound stays on until I turn off the machine.

Of course I could mute it, but finding out how to fix the problem is so much more fun.

I assume the sound output of your tv card goes through line in. Try KMix to deselect line in.