Comment 2 for bug 841463

it seems to be an issue with all the python plugins, try to activate any and you'll get:

/usr/lib/python2.7/dist-packages/gobject/constants.py:24: Warning: g_boxed_type_register_static: assertion `g_type_from_name (name) == 0' failed
  import gobject._gobject
Traceback (most recent call last):
  File "/usr/lib/rhythmbox/plugins/lyrics/lyrics.py", line 35, in <module>
    from LyricsConfigureDialog import LyricsConfigureDialog
  File "/usr/lib/rhythmbox/plugins/lyrics/LyricsConfigureDialog.py", line 36, in <module>
    class LyricsConfigureDialog (GObject.Object, PeasGtk.Configurable):
  File "/usr/lib/rhythmbox/plugins/lyrics/LyricsConfigureDialog.py", line 38, in LyricsConfigureDialog
    object = GObject.property(type=GObject.Object)
  File "/usr/lib/python2.7/dist-packages/gi/_gobject/propertyhelper.py", line 111, in __init__
    self.type = self._type_from_python(type)
  File "/usr/lib/python2.7/dist-packages/gi/_gobject/propertyhelper.py", line 202, in _type_from_python
    raise TypeError("Unsupported type: %r" % (type_,))
TypeError: Unsupported type: <type 'gobject.GObject'>

similar error is raised for every other plugin there.