I just downloaded matplotlib- from sourceforge.

I have an existing Application that works fine with
python : 2.5.4 final 0
pyGTK : 2.12.1
GTK+ : 2.14.7
numpy : 1.2.1
matplotlib :

Now I am trying the same App on
python version : 2.6.0 final 0
pyGTK version : 2.12.1
gtk+ version : 2.16.2
numpy version : 1.3.0
matplotlib version:

I got the following traceback, I'm wondering:
     - Am I looking at changes due to the different matplotlib versions?
    - Are some bits are missing in the downloaded installer ?
     - or is there incompatibility with the newer versions of GTK?

importing matplotlib
Traceback (most recent call last):
  File "C:\SVNproj\FrictionTests2\", line 17, in <module>
    from matplotlib.backends.backend_gtk import FigureCanvasGTK as FigureCanvas
  File "C:\Python26\Lib\site-packages\matplotlib\backends\", line 25, in <module>
    from matplotlib.backends.backend_gdk import RendererGDK, FigureCanvasGDK
  File "C:\Python26\Lib\site-packages\matplotlib\backends\", line 29, in <module>
    from matplotlib.backends._backend_gdk import pixbuf_get_pixels_array
ImportError: No module named _backend_gdk

Thanks for any clues