Errors during xmldiff install on xp

[M Ross]

Getting the following error msgs when trying to install the xmldiff
module:

c:\Python22\include\pyconfig.h(37) : fatal error C1083: Cannot open
include file: 'io.h': No such file or directory

running 
> python setup.py install
from the xmldiff directory.

io.h is on my machine-I have VS.NET installed.  It originally was
unable to find mspdb70.dll.  That was solved by adding the dll
location to my PATH.   However, it doesn't work for io.h.

How do I configure my setup so the xmldiff install will find all
required files?

I am a python newbie...

Thanks for your time.
Mike