Hi,I wont be much help because I am on a dialup.I am useing the Knoppix_3.1-16-10-2002-EN.iso and as others have reported the netcardconfig just flashes and goes away when run from the KNOPPIX menu.But I can start the program by opening an xterm as root and typeing "netcardconfig".I dont have a netcard in my box so thats what the xdialog pops up and tells me but if you have a card it should get it working (it has for others).
I have had some people say that command is no longer good with the 11-08-2002 iso.While you are waiting for more answers here stop my the Knoppix irc channel at irc.openprojects.net and join #knoppix.Quite a few people have solved the network problem after a hdd install in that room.Also browse the EN forums on the main Knoppix page.