"modules" listing fails in python2.5 command prompt

When python-matplotlib is installed under Feisty, I find that the interactive python2.5 prompt fails when I try help() -> modules.

See the detailed error message below:

help> modules

Please wait a moment while I gather a list of all available modules...

/usr/lib/python2.5/site-packages/apt/__init__.py:18: FutureWarning: apt API not stable yet
  warnings.warn("apt API not stable yet", FutureWarning)
Data Dir: /usr/share/deskbar-applet
Handlers Dir: ['/home/paulm/.gnome2/deskbar-applet/handlers', '/usr/lib/deskbar-applet/handlers']
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.5/site-packages/site.py", line 351, in __call__

  File "/usr/lib/python2.5/pydoc.py", line 1649, in __call__
    self.interact()
  File "/usr/lib/python2.5/pydoc.py", line 1667, in interact
    self.help(request)
  File "/usr/lib/python2.5/pydoc.py", line 1683, in help
    elif request == 'modules': self.listmodules()
  File "/usr/lib/python2.5/pydoc.py", line 1804, in listmodules
    ModuleScanner().run(callback)
  File "/usr/lib/python2.5/pydoc.py", line 1855, in run
    for importer, modname, ispkg in pkgutil.walk_packages():
  File "/usr/lib/python2.5/pkgutil.py", line 125, in walk_packages
    for item in walk_packages(path, name+'.', onerror):
  File "/usr/lib/python2.5/pkgutil.py", line 125, in walk_packages
    for item in walk_packages(path, name+'.', onerror):
  File "/usr/lib/python2.5/pkgutil.py", line 110, in walk_packages
    __import__(name)
  File "/usr/lib/python2.5/site-packages/matplotlib/enthought/resource/__init__.py", line 2, in <module>
    from resource_manager import ResourceManager
  File "/usr/lib/python2.5/site-packages/matplotlib/enthought/resource/resource_manager.py", line 20, in <module>
    from resource_reference import ImageReference
  File "/usr/lib/python2.5/site-packages/matplotlib/enthought/resource/resource_reference.py", line 11, in <module>
    class ResourceReference(HasTraits):
  File "/usr/lib/python2.5/site-packages/matplotlib/enthought/resource/resource_reference.py", line 20, in ResourceReference
    resource_factory = Instance(ResourceFactory) # ReadOnly
  File "/usr/lib/python2.5/site-packages/matplotlib/enthought/traits/traits.py", line 531, in Instance
    module = stack(1)[1][0].f_globals[ '__name__' ] )
  File "/usr/lib/python2.5/inspect.py", line 885, in stack
    return getouterframes(sys._getframe(1), context)
  File "/usr/lib/python2.5/inspect.py", line 866, in getouterframes
    framelist.append((frame,) + getframeinfo(frame, context))
  File "/usr/lib/python2.5/inspect.py", line 835, in getframeinfo
    raise TypeError('arg is not a frame or traceback object')
TypeError: arg is not a frame or traceback object