yep, looks like the nic card in your linux box is not configured. perhaps the driver is not getting loaded successfully, or maybe you don't have a driver at all for your particular nic. it'll take some troubleshooting.
try typing 'dmesg | less' and look for errors regarding eth0. also try 'ifconfig eth0 up' to see if your system perhaps just didn't bring up the interface. if it comes up, then run 'dhclient' (assuming you're modem is running dhcp).
did you install mandrake before or after the network card was installed? if before, you might just have to run 'kudzu' or 'harddrake' to see if your system can search for and find your card, and load the appropriate drivers. if the card was already in place when you installed mandrake, you either don't have a linux-compatible nic card (see mandrake's hardware compatibility list on their web site), or you'll have to hunt for a driver on the internet somewhere (like maybe the card vendor's web site ... ?).