Possible Duplicate:
How to fix 'Check your Internet connection' error in software center?
I am using Ubuntu 11.10 . I have a problem with the Software Center. I am not able to install anything from it. After I entered my authorisation password it gives the following error:
Failed to download package files check your internet connection.
After that it says
Requires installation of untrusted packages. The action would require the installation of packages from not authenticated sources.