Error after running script several times

I'm using Tkinter as the backend display for
matplotlib and also using IDLE -n. It works fine the
first several times I run it but ends up crashing and
taking down IDLE and pythonw.exe with it after ~10
runs of the script. I know this is not the best way
to use matplotlib right now. Anyway, here's the
plotting part of the script (.matplotlib set to
interactive mode)

if useMatplotlib:
    yrange = 1.5
    wfList = [p1, p2, p3]
    close() # close last plot window if still open
    nplots = len(waveformList)
    i = 0
    for p in wfList:
        i +=1
        subplot(nplots,1,i)
        plot(p, color='#7070a0')
        axis([0, totalPoints, -yrange, yrange])
        ylabel('Volts')
        grid(True)

Here's the eventual error message:

Traceback (most recent call last):
Exception in Tkinter callback
Traceback (most recent call last):
  File "C:\Python23\lib\lib-tk\Tkinter.py", line 1345,
in __call__
  File
"C:\Python23\lib\site-packages\matplotlib\backends\backend_tkagg.py",
line 120, in resize
  File
"C:\Python23\lib\site-packages\matplotlib\backends\backend_tkagg.py",
line 127, in show
  File
"C:\Python23\lib\site-packages\matplotlib\backends\backend_agg.py",
line 342, in draw
  File
"C:\Python23\lib\site-packages\matplotlib\artist.py",
line 88, in draw
  File
"C:\Python23\lib\site-packages\matplotlib\figure.py",
line 83, in _draw
  File
"C:\Python23\lib\site-packages\matplotlib\artist.py",
line 88, in draw
  File
"C:\Python23\lib\site-packages\matplotlib\axes.py",
line 527, in _draw
  File
"C:\Python23\lib\site-packages\matplotlib\artist.py",
line 88, in draw
  File
"C:\Python23\lib\site-packages\matplotlib\axis.py",
line 395, in _draw
  File
"C:\Python23\lib\site-packages\matplotlib\artist.py",
line 88, in draw
  File
"C:\Python23\lib\site-packages\matplotlib\axis.py",
line 93, in _draw
  File
"C:\Python23\lib\site-packages\matplotlib\artist.py",
line 88, in draw
  File
"C:\Python23\lib\site-packages\matplotlib\text.py",
line 87, in _draw
  File
"C:\Python23\lib\site-packages\matplotlib\backends\backend_agg.py",
line 199, in draw_text
  File
"C:\Python23\lib\site-packages\matplotlib\backends\backend_agg.py",
line 227, in compute_text_offsets
  File
"C:\Python23\lib\site-packages\matplotlib\backends\backend_agg.py",
line 257, in _get_agg_font
RuntimeError: Could not load the facefile
  File "C:\Documents and Settings\dlbrown\My
Documents\Python Scripts\gen_nonlinear_error.py", line
114, in ?
  File
"C:\Python23\lib\site-packages\matplotlib\matlab.py",
line 942, in plot
  File
"C:\Python23\lib\site-packages\matplotlib\backends\backend_tkagg.py",
line 46, in draw_if_interactive
  File
"C:\Python23\lib\site-packages\matplotlib\backends\backend_tkagg.py",
line 127, in show
  File
"C:\Python23\lib\site-packages\matplotlib\backends\backend_agg.py",
line 342, in draw
  File
"C:\Python23\lib\site-packages\matplotlib\artist.py",
line 88, in draw
  File
"C:\Python23\lib\site-packages\matplotlib\figure.py",
line 83, in _draw
  File
"C:\Python23\lib\site-packages\matplotlib\artist.py",
line 88, in draw
  File
"C:\Python23\lib\site-packages\matplotlib\axes.py",
line 527, in _draw
  File
"C:\Python23\lib\site-packages\matplotlib\artist.py",
line 88, in draw
  File
"C:\Python23\lib\site-packages\matplotlib\axis.py",
line 395, in _draw
  File
"C:\Python23\lib\site-packages\matplotlib\artist.py",
line 88, in draw
  File
"C:\Python23\lib\site-packages\matplotlib\axis.py",
line 93, in _draw
  File
"C:\Python23\lib\site-packages\matplotlib\artist.py",
line 88, in draw
  File
"C:\Python23\lib\site-packages\matplotlib\text.py",
line 87, in _draw
  File
"C:\Python23\lib\site-packages\matplotlib\backends\backend_agg.py",
line 199, in draw_text
  File
"C:\Python23\lib\site-packages\matplotlib\backends\backend_agg.py",
line 227, in compute_text_offsets
  File
"C:\Python23\lib\site-packages\matplotlib\backends\backend_agg.py",
line 257, in _get_agg_font
RuntimeError: Could not load the facefile

Also, not sure if it's relevant but if I try to
continue in IDLE I sometimes get "too many files open"
errors as well as mostly non-working windows. Any
suggestions?

-- David

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