Try this : if you can boot-up another system that works with your netcard, use it to obtain your router or modem address as applicable, and (optionally, to avoid unnecessary proliferation of addresses), the address that it allocates to your network card under DHCP.
They are likely to be of the forms (substitute your own figures):

192.168.A.B for the modem/router
192.168.A.C for the netcard

Then in Knoppix netcardconfig answer NO to DHCP,

enter 192.168.A.C for the netcard address
enter 255.255.255.0 Subnet Mask
enter 192.168.A.255 Broadcast
enter 192.168.A.B for Nameserver and Gateway

(Reference: http://www.knoppix.net/forum/viewtop...287&highlight= )

Also you might have to command: ifconfig eth0 mtu 1500

(Reference: http://www.knoppix.net/forum/viewtopic.php?t=26867 )

Good luck