import matplotlib._png as _png 导入：错误：DLL 加载失败：找不到指定的模块

我使用 Anaconda Python 发行版：Python 2.7 x64 和 Windows 7 SP1 x64 Ultimate。

当我做import matplotlib.pyplot I get ImportError: DLL load failed: The specified module could not be found.。可能是什么问题？

完整的错误堆栈：

Traceback (most recent call last):
  File "C:\svn\hw4\code\test_con.py", line 1, in <module>
    import matplotlib.pyplot 
  File "C:\Anaconda\lib\site-packages\matplotlib\pyplot.py", line 27, in <module>
    import matplotlib.colorbar
  File "C:\Anaconda\lib\site-packages\matplotlib\colorbar.py", line 34, in <module>
    import matplotlib.collections as collections
  File "C:\Anaconda\lib\site-packages\matplotlib\collections.py", line 27, in <module>
    import matplotlib.backend_bases as backend_bases
  File "C:\Anaconda\lib\site-packages\matplotlib\backend_bases.py", line 56, in <module>
    import matplotlib.textpath as textpath
  File "C:\Anaconda\lib\site-packages\matplotlib\textpath.py", line 22, in <module>
    from matplotlib.mathtext import MathTextParser
  File "C:\Anaconda\lib\site-packages\matplotlib\mathtext.py", line 63, in <module>
    import matplotlib._png as _png
ImportError: DLL load failed: The specified module could not be found.

conda update -f numpy, conda update -f libpng, and conda update -f matplotlib没有帮助。

输出conda list matplotlib:

C:\Anaconda>conda list matplotlib
# packages in environment at C:\Anaconda:
#
matplotlib                1.4.3               np110py27_2
matplotlib-venn           0.11                      <pip>

运行后出现问题conda update --all.

我通过将 [Anaconda]/Library/bin 添加到我的 PATH 中，在 Windows 计算机上修复了此问题。