Try use knoppix built-in pppoe first.

At the bottom left of your taskbar you will see knoppix penguin icon, click that and choose to configure your networkcard.
Don't choose DHCP broadcast, set manually your ip(ex: 192.168.0.2), dns(given to you by isp), gateway (you can leave this blank)...etc. You can use dhcp broadcast if you are using router, and the router is set to broadcast dhcp.

After you are done with netcard config, run pppoe config...it will ask your account name and password.