Comment 22 for bug 896836

I came across the same error when running "quickly run", after I added

import pygtk
pygtk.require('2.0')
import gtk

to my FirstWindow.py (main window)

the output:
$ quickly run
/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
/usr/lib/python2.7/dist-packages/gtk-2.0/gtk/__init__.py:40: Warning: specified class size for type 'PyGtkGenericCellRenderer' is smaller than the parent type's 'GtkCellRenderer' class size
  from gtk import _gtk
/usr/lib/python2.7/dist-packages/gtk-2.0/gtk/__init__.py:40: Warning: g_type_get_qdata: assertion 'node != NULL' failed
  from gtk import _gtk

in my case command python -> help('modules') works

Ubuntu 14.04 LTS, Python 2.7.6