I was at a customer site, and it was required that I connect to their wired network. Everyone in the customer site could connect to the wired network, except me... :) Why? well probably two reasons, I had a ubuntu machine where as everyone else had windows, and I had a machine I used at WSO2, with WSO2 network.
Hence, I googled a bit, and figured out the issue. The issue in my case was that the /etc/network/interfaces file had some unwanted lines in there.
If you do happen to come across the same issue, you could try this as well.
Comment or delete any lines in the /etc/network/interfaces file except for the lines
iface lo inet loopback
I personally would comment.. :)