Can't connect to the Internet with my ZyXEL PRESTIGE 630

Hi, I can't go online with my Knoppix 3.7.
I love the idea of getting away from Windows and very much like the look of Knoppix. Before installing it onto my HD I wanted to try several things with it.
The problem is, I can't even get into the internet and this disillusions me a little bit.
The modem I use is connected via an USB port and seems to be detected when booting from the CD, as the lights of the modem come on and stay on.
After that it seems no more action. When I open Mozilla browser it doesn't work because I'm not online.
When trying to configure the Internet via "knoppix/network/internet/adsl/pppoe" the following message appears three times in the black window "pppoe-discovery: timeout waiting for PADO packets: success"
Than a new window opens and it says "Sorry, I scanned 1 interface(s), but Acess concentrator of your provider
did not respond. Please check your network and modem cables. Another
reason for the scan failure may also be another running pppoe process which controls the modem."
Please help - I'm really in dispair here.

Lupo