[mod_python] IOError: [Errno 2] No such file or directory...(etc)

Okay, I know this has been discussed many times before, and I am
aware of the fix on the FAQ.  However, I have a few issues:

1) My error says "IOError" instead of the "OSError" that everyone
else has reported.
2) using Python 2.2.1, Apache 1.3.26, Modpython 2.7.8, on WinXP
3) Since the python patch for this was closed in Aug-2001, any idea
why it isn't in Python 2.2.1, released Apr-2002?  
4) I went ahead & patched pythonrun.c and recompiled my Python 2.2.1.
The FAQ says to rebuild mod_python, but I don't know how to on
Windows, and I suspect 2.7.8 might already have the fix?.  

Can anyone assist with rebuilding mod_python on Windows?  What effect
would that have since it doesn't include pythonrun.c in the
mod_python build?  Any other ideas regarding the problem? (output is
below)

-Kevin

**** output ****

Mod_python error: "PythonHandler mod_python.publisher"

Traceback (most recent call last):

  File "C:\...\python\Lib\mod_python\apache.py", line 193, in Dispatch
    result = object(req)

  File "C:\...\python\Lib\mod_python\publisher.py", line 171, in
handler
    result = apply(object, (), args)

  File "c:/.../mywww\imgsvr.py", line 77, in get
    fd = open( filenm, "rb" )

IOError: [Errno 2] No such file or directory:
'z:\\FILES\\up\\oak_20020730\\01638764.BCK.jpg'

**** end of output ****

Notes:
I'm trying to access a file on my local network.  I have tried
different drive letters on my local network (& UNC paths instead of
drive letters).  The only time it works is when I use the local "C:"
for the path.  Even if I do a "subst e: c:\" and try that (E:\...),
it fails.  I even tried messing with <Directory> entries in Apache to
no avail.

And yes, the code works fine when outside of Apache/Mod_python.