My Knoppix 2.7 required root password when I run some progra

When I run Ethereal network analyser form my live KNoppix CD, it opens but ask root password, when I leave it blank and Click OK, it say wrong password. I did not do any setting in Knoppix 3.7 I just booted my computer with that and start using it. By the way I am posing this messege via Knoppix 3.7 booted CD. Please help me.

Thanks

read this link and you wil be enlightened.
http://www.knoppix.net/wiki/Root
actually browse trough these when you have a Q, they contain a surprising amount of usefull information
http://www.knoppix.net/wiki/Main_Page