It seems you have no name resolution.
This can be fixed by following the advice int this wiki
http://www.linuxmint.com/wiki/index.php ... e_programs
Oddly I have to follow the advice to get internet for apt, ubiqity and mintUpdate, but not for Firefox and Thunderbird
I can't connect to the router ip from the Mint
which I "took in" first after writing the answer above tells another story
What happens if you ping the router - you can ping from network tools in the control center or from the terminal