first of all: is it possible to download files on knoppix?
if yes:

my mp3 player doesn't work (xmms). it plays 2-3 songs (if at all) and then it stops working and i get this message:
img3.imageshack.us/img3/5317/soundkarte.jpg
i was told i should install arts plug in. when i try to install it, it asks me for a password. i tried "su" and it doesn't work. i tried to set password by typing "passwd" in the command shell but when the "Enter new UNIX password" appears i can't type anything. same thing happens when i try to enter the password installing arts plug in.

can anyone help me?
thanks.

Are you trying to install the plugin as a normal user? I mean, does it ask for a root - password?

A lot of times those password prompts don't echo what you are typing...have you tried typing something in and pressing enter? Does it acknowledge and ask something else?

i solved my problem... well, not solved, but realized what was wrong. like i thought it's not possible to install programs on livecd. oh well. i'm installing gentoo anyway