Traceback (most recent call last):
  File "/usr/lib/pitivi/python/pitivi/ui/mainwindow.py", line 520, in _deleteCb
    if not self.app.shutdown():
  File "/usr/lib/pitivi/python/pitivi/application.py", line 287, in shutdown
    if Pitivi.shutdown(self):
  File "/usr/lib/pitivi/python/pitivi/application.py", line 162, in shutdown
    if self.projectManager.current and not self.projectManager.closeRunningProject():
  File "/usr/lib/pitivi/python/pitivi/projectmanager.py", line 158, in closeRunningProject
    self.emit("project-closed", self.current)
  File "/usr/lib/pitivi/python/pitivi/signalinterface.py", line 145, in emit
    *args, **kwargs)
  File "/usr/lib/pitivi/python/pitivi/signalinterface.py", line 119, in emit
    res = cb(*ar, **kw)
  File "/usr/lib/pitivi/python/pitivi/ui/mainwindow.py", line 829, in _projectManagerProjectClosedCb
    self.viewer.setPipeline(None)
  File "/usr/lib/pitivi/python/pitivi/ui/viewer.py", line 99, in setPipeline
    self._disconnectFromPipeline()
  File "/usr/lib/pitivi/python/pitivi/ui/viewer.py", line 165, in _disconnectFromPipeline
    self.pipeline.stop()
  File "/usr/lib/pitivi/python/pitivi/pipeline.py", line 311, in stop
    self.setState(STATE_READY)
  File "/usr/lib/pitivi/python/pitivi/pipeline.py", line 269, in setState
    raise PipelineError("Failure changing state of the gst.Pipeline to %r, currently reset to NULL" % state)
PipelineError: Failure changing state of the gst.Pipeline to <enum GST_STATE_READY of type GstState>, currently reset to NULL