Re: [Trisquel-users] Cannot install GNOME Shell on Trisquel 7 I18N 64-bit.

[mampir]

I'm using gnome-shell Trisquel 7 I18N 64-bit, so I know it should work.
Try updating you packages before installing:
sudo aptitude update

I'm more familiar with the output of aptitude, so try installing with it:

sudo aptitude install gnome-shell

You don't need to install the Mutter package.  It's useful only, if you want  
to use Mutter without GNOME Shell.