Unable to get updates

I am having trouble while connecting to the update center. I get the following error Warning: Cannot connect to online repository (mirror.freepbx.org). Online modules are not available…
I have tried to ping it from the server and even there I get the error that host not reachable.
I have checked my DNS and Gateway settings they seem to be correct.The only thing I could figure out that normally when users connect to the internet they have to enter proxy in their web browser and that option is not available in AsteriskNow 1.7.
Does anyone out there have a solution to this problem?

Umer Hamid