ok to ignore warning on first import?

The first time I "import pylab" after installing matplotlib
I get many warnings (below). This is 0.87.7 under Python 2.5.
Is ignoring these the right thing to do? (I seem to be up and running.)
Alan Isaac

Warning (from warnings module):
  File "/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/matplotlib/font_manager.py", line 455
    warnings.warn("Could not open font file %s"%fpath)
UserWarning: Could not open font file /Library/Fonts/NISC18030.ttf

Warning (from warnings module):
  File "/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/matplotlib/font_manager.py", line 455
    warnings.warn("Could not open font file %s"%fpath)
UserWarning: Could not open font file /System/Library/Fonts/Helvetica LT MM

Warning (from warnings module):
  File "/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/matplotlib/font_manager.py", line 455
    warnings.warn("Could not open font file %s"%fpath)
UserWarning: Could not open font file /System/Library/Fonts/HelveLTMM

Warning (from warnings module):
  File "/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/matplotlib/font_manager.py", line 455
    warnings.warn("Could not open font file %s"%fpath)
UserWarning: Could not open font file /System/Library/Fonts/Times LT MM

Warning (from warnings module):
  File "/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/matplotlib/font_manager.py", line 455
    warnings.warn("Could not open font file %s"%fpath)
UserWarning: Could not open font file /System/Library/Fonts/LastResort.dfont

Warning (from warnings module):
  File "/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/matplotlib/font_manager.py", line 455
    warnings.warn("Could not open font file %s"%fpath)
UserWarning: Could not open font file /System/Library/Fonts/Keyboard.dfont

Warning (from warnings module):
  File "/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/matplotlib/font_manager.py", line 455
    warnings.warn("Could not open font file %s"%fpath)
UserWarning: Could not open font file /System/Library/Fonts/TimesLTMM