No set_antialiased?

My first trial produced the following error message.
What problem do you think is in my installation?
I am using GtkAgg backend for matplotlib 0.6.1 version in Mandrake 10
and python 2.3.3.
Thanks.

from matplotlib.matlab import *
x=arange(10)
plot(x)

Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/usr/lib/python2.3/site-packages/matplotlib/matlab.py", line
1176, in plot
    lines = gca().plot(*args, **kwargs)
  File "/usr/lib/python2.3/site-packages/matplotlib/matlab.py", line
762, in gca
    return get_current_fig_manager().get_current_axis()
  File "/usr/lib/python2.3/site-packages/matplotlib/matlab.py", line
251, in get_current_fig_manager
    gcf() # creates an active figure as a side effect
  File "/usr/lib/python2.3/site-packages/matplotlib/matlab.py", line
771, in gcf
    return figure()
  File "/usr/lib/python2.3/site-packages/matplotlib/matlab.py", line
691, in figure
    figManager = new_figure_manager(num, figsize, dpi, facecolor,
edgecolor, frameon)
  File
"/usr/lib/python2.3/site-packages/matplotlib/backends/backend_gtkagg.py", line 25, in new_figure_manager
    thisFig = Figure(*args, **kwargs)
  File "/usr/lib/python2.3/site-packages/matplotlib/figure.py", line 52,
in __init__
    facecolor=facecolor, edgecolor=edgecolor,
  File "/usr/lib/python2.3/site-packages/matplotlib/patches.py", line
130, in __init__
    Patch.__init__(self, **kwargs)
  File "/usr/lib/python2.3/site-packages/matplotlib/patches.py", line
48, in __init__
    self.__dict__['set_%s'%abbrev] = getattr(self, 'set_%s'%func)
AttributeError: Rectangle instance has no attribute 'set_antialiased'

···

--
Daehyok Shin