Cannot start Jack

[Peter Nabbefeld <peter.nabbefeld@xxxxxx>]

Hello,

I've installed jack2-dbus, but cannot start jack:

$ jack_control start
--- start
DBus exception: org.jackaudio.Error.Generic: Failed to open server

I'm in the audio group, dmesg doesn't show anything (I've cleared it 
before issuing the command, just to make sure I don't miss any line).

Kind regards
Peter