Explained here : http://www.checkupdown.com/status/E407.html
Originally Posted by Gakhar
Please check this out : http://askubuntu.com/questions/88976...ation-required
If you prefer to use the Synaptic way (I prefer it over Software Center anyway), but have problem in downloading it too (in apt-get install synaptic), you can use the following command to get the URI of the package(s) to be downloaded for synaptic:
Then you can download them directly using your browser and install with dpkg -i * command.
apt-get install --print-uris synaptic