Problema de instalación con matplotlib Python [duplicado]

Tengo un problema después de instalar el paquete matplotlib y no puedo importar matplotlib.pyplot como plt . Cualquier sugerencia será muy apreciada.

>>> import matplotlib.pyplot as plt
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "//anaconda/lib/python2.7/site-packages/matplotlib-1.3.1-py2.7-macosx-10.5-x86_64.egg/matplotlib/pyplot.py", line 98, in <module>
    _backend_mod, new_figure_manager, draw_if_interactive, _show = pylab_setup()
  File "//anaconda/lib/python2.7/site-packages/matplotlib-1.3.1-py2.7-macosx-10.5-x86_64.egg/matplotlib/backends/__init__.py", line 28, in pylab_setup
    globals(),locals(),[backend_name],0)
  File "//anaconda/lib/python2.7/site-packages/matplotlib-1.3.1-py2.7-macosx-10.5-x86_64.egg/matplotlib/backends/backend_macosx.py", line 21, in <module>
    from matplotlib.backends import _macosx
**RuntimeError**: Python is not installed as a framework. The Mac OS X backend will not be able to function correctly if Python is not installed as a framework. See the Python documentation for more information on installing Python as a framework on Mac OS X. Please either reinstall Python as a framework, or try one of the other backends.

Feb 14 '14 23:02 J4cK