"[14.04] KDE Login Error "Could not start dbus. Can you call qdbus?"

[Bernard Gray]

Hi Guys,
Me again - the dist-upgrade on my 14.04 machine today yielded a
complete KDE Desktop failure. After I login (KDM) it drops me to a
wallpaper screen with a basic xorg window displaying:

 "Could not start dbus. Can you call qdbus?"

...and an [okay] button.
The okay button does nothing when you click it, and my desktop is unusable -

The system dbus is running, I assume this is referring to the session
dbus instance that is not starting. If I run qdbus in a tty:

$ DISPLAY=:0 qdbus
:1.0
org.freedesktop.DBus
$ echo $?
0

I've seen one other report of this on an unofficial(?) french ubuntu forum:
https://forum.ubuntu-fr.org/viewtopic.php?pid=16537651

I'm installing gnome as we speak to get running for now, will happily
do more troubleshooting if someone can guide me -

Regards,
Bernard Gray