I'm no guru on this sort of thing but it looks like there could be a DNS problem. Can you ping google or does it give errors too?
If that doesn't work, check and see what is in your resolv.conf file.
It should look something like this:
root@fireball / # cat /etc/resolv.conf
# Generated by net-scripts for interface eth0
root@fireball / #
If you have nothing in there, you can try putting the numbers I have above in yours. Those numbers are the DNS servers for Google so they should be safe enough, if you trust google.
There could be other causes for this but this is a likely one.