a little problem with quiver function and numarray

I obtain an error message when I tried to use the quiver sample:

Traceback (most recent call last):
  File "quiver_demo.py", line 8, in ?
    quiver( X, Y, U, V, 0.2, color=True )
  File "/usr/local/lib/python2.4/site-packages/matplotlib/pylab.py", line 2105, in quiver
    ret = gca().quiver(*args, **kwargs)
  File "/usr/local/lib/python2.4/site-packages/matplotlib/axes.py", line 894, in quiver
    if C:
  File "/usr/local/lib/python2.4/site-packages/numarray/generic.py", line 490, in __nonzero__
    raise RuntimeError("An array doesn't make sense as a truth value. Use any(a) or all(a).")
RuntimeError: An array doesn't make sense as a truth value. Use any(a) or all(a).

with:

cvs status lib/matplotlib/axes.py

···

===================================================================
File: axes.py Status: Up-to-date

   Working revision: 1.86
   Repository revision: 1.86 /cvsroot/matplotlib/matplotlib/lib/matplotlib/axes.py,v

and numarray 1.2.3

    N.