[Matplotlib-users] Error with bar charts

[<sto...@ya...>]

I receive an error when trying to plot barcharts.  To confirm it was 
nothing to do with my code, I tried running one of the demos provided and 
received the same error:

$ python barchart_demo.py
Traceback (most recent call last):
   File "barchart_demo.py", line 11, in ?
     p1 = bar(ind, menMeans, width, color='r', yerr=menStd)
   File "/usr/lib64/python2.4/site-packages/matplotlib/pylab.py", line 
1641, in bar
     ret =  gca().bar(*args, **kwargs)
   File "/usr/lib64/python2.4/site-packages/matplotlib/axes.py", line 2485, 
in bar
     xerr = asarray([xerr]*nbars, Float)
   File "/usr/lib64/python2.4/site-packages/numarray/numarraycore.py", line 
434, in asarray
     return array(seq, type=type, typecode=typecode, copy=0, dtype=dtype)
   File "/usr/lib64/python2.4/site-packages/numarray/numarraycore.py", line 
417, in array
     return fromlist(sequence,type,shape)
   File "/usr/lib64/python2.4/site-packages/numarray/numarraycore.py", line 
267, in fromlist
     arr.fromlist(seq)
ValueError: Invalid sequence.

Can't figure out the issue in numarray it is encountering.

I am brand spanking new to matplotlib and using python for scientific 
computing (amazing product; can't believe I didn't know about it before.) 
and would appreciate some help in getting started.  I apologise if it's 
something basic (couldn't find anything on google).

python 2.4.3
matplotlib 0.87.4
numarray-1.5.2
(Mandriva 2007 x64-64)

Thanks,
Suresh