Chances are the error message "server can not be found" is a DNS error.

As knoppix found the router, you need to know if the router is a combined, router/modem and is making the connection to the internet. You need to run the network card configuration utility from knoppix, followed by ipconfig at a terminal. Finally
the contents of resolv.conf also need to be known.
Post the outputs of:
ifconfig
cat /etc/resolv.conf
route