"No default terminal command has been defined" in Gnome 3

I have just installed arch in my new laptop and setup Mod4+Enter to launch gnome-terminal on gnome 3, but it didn't come out. After google it, the reason turned out to be: Gnome 3 is pured installed. Here's the way to solve the problem, just run two commands below:
gconftool-2 --type=string --set "/desktop/gnome/applications/terminal/exec" "gnome-terminal"
gconftool-2 --type=string --set "/desktop/gnome/applications/terminal/exec_args" -- "-x"