[Trisquel-users] Re : Cannot Configure VPN

[magicbanana]

Please read the error message and *try* to solve your problem by yourself.  
aptitude and apt-get say:
E: Unable to locate package install

It is simply because you typed "install" twice (the second is therefore  
considered a package name).

As for the output of 'sudo aptitude install network-manager-gnome', it does  
not do anything because network-manager-gnome already is on your system.

Your software sources seem to be a mess. Can you show us the output of:
$ cat /etc/apt/sources/list