GStreamer bus error when adding an instrument during playback

Here is my error message :

GStreamer a rencontré une erreur générale de flux.
gstbasesrc.c(2330): gst_base_src_loop (): /GstPipeline:timeline/GstBin:playbackbin/GstBin:Instrument_6/GnlComposition:gnlcomposition2/GnlSource:gnlsource6/GstAudioTestSrc:audiotestsrc3:
streaming task paused, reason not-linked (-1)

Fabrice, which version of Jokosher are you using?
If you are using the latest version (0.11.3) please browse to the folder ~/.local/share/jokosher/ and delete all *.dot files.
Then run Jokosher with GStreamer debugging enabled, with this command:
jokosher -g

And when you encounter this error it should generate many (5 to 10) *.dot files in ~/.local/share/jokosher/. If you could attach all those dot files to this bug report it would be very helpful. Thanks.

Here my .dot file.

Terminal log follows:

alessio@alessio-laptop:~$ LC_ALL=en jokosher -d -g

(process:32427): Gtk-WARNING **: Locale not supported by C library.
 Using the fallback 'C' locale.
Locale unsupported, defaulting to english for all Jokosher specific text.
Filling LADSPA Registry
  162 LADSPA effects loaded
 Reading in presets...
 ...done.
Cannot find "lame" plugin, disabling: "lame"
Cannot find "directsoundsink" plugin, disabling: "directsoundsink"
Cannot find "osxaudiosink" plugin, disabling: "osxaudiosink"
Cannot find "dshowaudiosrc" plugin, disabling: "dshowaudiosrc"
Cannot find "osxaudiosrc" plugin, disabling: "osxaudiosrc"
Loading extensions:
 importing extension Fullscreen.py
 importing extension jokosher-dbus.py
 importing extension GNOMEAudioProfiles.py
 importing extensions from directory /usr/share/jokosher/extensions
Pidgin Extension: Couldn't connect to the pidgin dbus interface. Is pidgin running?
 cannot register extension PidginExtension-0.1-py2.6
 importing extensions from directory /home/alessio/.local/share/jokosher/extensions
Attempting to open: /home/alessio/Documenti/Test/joko/test/test.jokosher
Using custom pipeline for audio sink: jackaudiosink
added project playback bin to the pipeline
added adder0 to project playbackbin
added levelcaps to project playbackbin
added audioconvert0 to project playbackbin
added MasterLevel to project playbackbin
added bin0 to project playbackbin
Loading project file version 0.11.1
added instrument playbackbin to adder playbackbin 0
linked instrument playbackbin to adder (project)
LOG COMMAND: ('P', 'DeleteInstrument', [0]) from 42070672
create file source
creating SingleDecodeBin
file uri is: file:///home/alessio/Documenti/Test/joko/test/audio/08_Jamin-%C3%A0_1.mp3
setting event properties:
  media-start = 0
  media-duration = 0
  caps = audio/x-raw-int; audio/x-raw-float
  priority = 2
  start = 0
  duration = 0
LOG COMMAND: ('I0', 'DeleteEvent', [1]) from 42070672
creating SingleDecodeBin
file uri is: file:///home/alessio/Documenti/Test/joko/test/audio/08_Jamin-%C3%A0_1.mp3
setting event properties:
  media-start = 0
  media-duration = 0
  caps = audio/x-raw-int; audio/x-raw-float
  priority = 2
  start = 0
  duration = 0
creating SingleDecodeBin
file uri is: file:///home/alessio/Documenti/Test/joko/test/audio/08_Jamin-%C3%A0_1.mp3
setting event properties:
  media-start = 0
  media-duration = 307800816326
  caps = audio/x-raw-int; audio/x-raw-float
  priority = 2
  start = 0
  duration = 307800816326
received group of tags
received group of tags
received group of tags
received group of tags
play() in Project.py
current state: GST_STATE_NULL
Preparing the controller
FADE POINT: time(0.00) vol(0.99)
FADE POINT: time(307.80) vol(0.99)
Set extra zero fade point
just set state to PAUSED
STATE CHANGED
-- status: GST_STATE_CHANGE_ASYNC
-- pending: GST_STATE_PAUSED
-- new: GST_STATE_READY
STATE CHANGED
-- status: GST_STATE_CHANGE_ASYNC
-- pending: GST_STATE_PAUSED
-- new: GST_STATE_READY
STATE CHANGED
-- status: GST_STATE_CHANGE_ASYNC
-- pending: GST_STATE_PAUSED
-- new: GST_STATE_READY
STATE CHANGED
-- status: GST_STATE_CHANGE_ASYNC
-- pending: GST_STATE_PAUSED
-- new: GST_STATE_READY
STATE CHANGE...

O GStreamer encontrou um erro geral no fluxo.
If this problem persists consider reporting a bug using the link in the help menu.
I NEED HELP WITH THIS ERROR