Question: I have Ubuntu-Gnome 14.04 (Gnome 3.12.2).

When I try to run `gnome-terminal` by following command :

```
$ gnome-terminal
Error constructing proxy for org.gnome.Terminal: /org/gnome/Terminal/Factory0: 
Error calling StartServiceByName for org.gnome.Terminal:
GDBus.Error:org.freedesktop.DBus.Error.Spawn.ChildExited: 
Process /usr/lib/gnome-terminal/gnome-terminal-server exited with status 8

```

Answer: 
This is a winner for me:

```
/usr/bin/dbus-launch /usr/bin/gnome-terminal &

```

as learned [here](https://bbs.archlinux.org/viewtopic.php?pid=1828182#p1828182)
This might be an issue with your locales. Either add `LANG=en_US.UTF-8` to `/etc/locale.conf` and reboot or delete that file altogether (`sudo rm /etc/locale.conf && sudo locale-gen en_US.UTF-8 && sudo dpkg-reconfigure locales`) and reboot.