использование пакета статистики по scipy ошибке в Python?

Я пытаюсь использовать scipy пакет статистики в Python и получаю следующую ошибку (на Mac OS X):

$ python
Python 2.6.5 (r265:79359, Mar 24 2010, 01:32:55) 
[GCC 4.0.1 (Apple Inc. build 5493)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import scipy
>>> from scipy import stats

Я затем получаю ошибку:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/scipy-0.9.0.dev-py2.6-macosx-10.6-universal.egg/scipy/stats/__init__.py", line 7, in <module>
    from stats import *
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/scipy-0.9.0.dev-py2.6-macosx-10.6-universal.egg/scipy/stats/stats.py", line 202, in <module>
    import scipy.special as special
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/scipy-0.9.0.dev-py2.6-macosx-10.6-universal.egg/scipy/special/__init__.py", line 8, in <module>
    from basic import *
  File "/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/scipy-0.9.0.dev-py2.6-macosx-10.6-universal.egg/scipy/special/basic.py", line 6, in <module>
    from _cephes import *
ImportError: dlopen(/Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/scipy-0.9.0.dev-py2.6-macosx-10.6-universal.egg/scipy/special/_cephes.so, 2): Symbol not found: _aswfa_
  Referenced from: /Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/scipy-0.9.0.dev-py2.6-macosx-10.6-universal.egg/scipy/special/_cephes.so
  Expected in: flat namespace
 in /Library/Frameworks/Python.framework/Versions/2.6/lib/python2.6/site-packages/scipy-0.9.0.dev-py2.6-macosx-10.6-universal.egg/scipy/special/_cephes.so

Какая-либо идея, что могло происходить здесь?

спасибо.