Errors importing Matplotlib

I built matplotlib on linux from source using:

python build
python install --home=/home/tom

when I try to import

import pylab

Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/home/tom/lib/python/", line 1, in ?
    from matplotlib.pylab import *
  File "/home/tom/lib/python/matplotlib/", line 199, in ?
    import backends
  File "/home/tom/lib/python/matplotlib/backends/", line 19, in ?
  File "/home/tom/lib/python/matplotlib/backends/",
line 11, in ?
    from backend_gtk import gtk, FigureManagerGTK, FigureCanvasGTK,\
  File "/home/tom/lib/python/matplotlib/backends/", line 21, in ?
    from backend_gdk import RendererGDK
  File "/home/tom/lib/python/matplotlib/backends/", line 45, in ?
    from matplotlib._nc_backend_gdk import pixbuf_get_pixels_array
ImportError: No module named _nc_backend_gdk

When I look in the backends dir in
/home/tom/lib/python/matplotlib/backends i see the following files
which does not include the .so file for _nc_backend_gdk
__init__.pyc backend_gdk.pyc backend_qtagg.pyc backend_gtk.pyc backend_svg.pyc
backend_agg.pyc backend_gtkagg.pyc backend_template.pyc
backend_agg2.pyc backend_gtkcairo.pyc backend_tkagg.pyc
backend_cairo.pyc backend_paint.pyc backend_wx.pyc
backend_fltkagg.pyc backend_ps.pyc backend_wxagg.pyc
backend_gd.pyc backend_qt.pyc tkagg.pyc

Is there something I am doing wrong?