Browsers do not work, Internet works fine

I'm experiencing a weird problem, and I'm breaking my head! When I connect via Ethernet, neither Safari nor other browsers are able to connect: "Failed to open page" after a loooooong time. However: the Internet connection works fine, other applications (e.g., Skype, Transmission) are able to connect fine. Via airport/WiFi, there is no problem, all browsers work fine.

(I need to connect via Ethernet to install a new network server.)