Quote Originally Posted by Flanker
.... however I was having this problem before as well. .....
Do you mean you had this problem with Windows also, or just with Knoppix before you wiped the disk?

This is not a common problem, it might help someone help you if you listed all of your hardware, particularly the sound card in use and any related equipment. Is thew headphone plugged into the back of the computer or a jack in the front? If the front, you might try the back and see if the audio is there when it's not coming out the front.