looks like your ethernet device doesn't get an ip via dhcp. you may try assigning a fixed ip somewhere in the configuration files from you mandrake sys. anyway you can assign one manual with
"ifconfig eth0 192.168.1.2 netmask 255.255.255.0 up"
so it will be 192.168.1.2. you should get results back when pinging that interface. if it's allright add a route to your gateway (will likely be your router).
"route add default gw 192.168.1.1" <- ip of your router.
try ping the router to see if he's reachable. if you've further questions send them in or have a look at www.tldp.org.
there are a lot of useful howtos helping you getting various things to work. (linux network admin..)