look at your /etc/resolv.conf file. is there anything there. if no, add
and you have set the gateway on the linux box to the ip of your router right?
x.x.x.x being the ip of your dns servers.
to see if you can get out at all, try pinging 188.8.131.52
if you get a reply it is a dns issue, and the above should work. after you add the names restart the pc, or restart the services network and xinetd if you know how. restart will work if not.
let me know if this helps.