Comment # 23 on bug 1156501 from Fabian Vogt

(In reply to Dr. Werner Fink from comment #20)
> I should mention that dbus-launch requires X11 $DISPLAY ... and I really
> like to know *Why* a dbus launch depend on X11 screen?

It is meant only for X11. The man page explicitly states:

> To start a D-Bus session within a text-mode session, do not use dbus-launch. Instead, see dbus-run-session(1).