My platform is as follows
Centos 6.x (VirtualBox VM running on Win-7 host), Python 2.6.6, Matplotlib 1.3.1, Numpy 1.8.0, Scipy 0.14.0.dev-bb608ba
I am runnin
The first step in debugging this is to replace plt.show() by plt.savefig('foo.png'). If it works, the problem is most probably with the backend:
>>> import matplotlib
>>> matplotlib.get_backend()
'Qt4Agg'
Try switching backends and see if that helps: How to switch backends in matplotlib / Python
If that does not help either, make sure you have all the dependencies (http://matplotlib.org/users/installing.html) --- I'd just reinstall from source. (not pip install matplotlib)