error with matplotlib installation

I am trying to install the matplotlib in my pc with the following configuration
Windows 7, 64



once i try to test the code i get the following error fir matplotlib:

import numpy
import numpy as np
import matplotlib
import matplotlib.pyplot as plt

Traceback (most recent call last):
File “<pyshell#5>”, line 1, in
import matplotlib.pyplot as plt
File “C:\Python26\lib\site-packages\matplotlib\”, line 23, in
from matplotlib.figure import Figure, figaspect
File “C:\Python26\lib\site-packages\matplotlib\”, line 16, in
import artist
File “C:\Python26\lib\site-packages\matplotlib\”, line 6, in
from transforms import Bbox, IdentityTransform, TransformedBbox, TransformedPath
File “C:\Python26\lib\site-packages\matplotlib\”, line 34, in
from matplotlib._path import affine_transform
ImportError: DLL load failed: %1 is not a valid Win32 application.

can someone help me with this ?