I have Moin Wiki running on windows xp IIS. I downloaded the diff.exe for windows and put it in my c:\windows\system32\ directory and it works fine from the command line, but an error shows up on the wiki page when I click the diff icon.
WindowsError: [Errno 5] Access is denied Python 2.1.2

A problem occurred while running a Python script. Here is the sequence of function calls leading up to the error, with the most recent (innermost) call first. The exception attributes are:
      args = (5, 'Access is denied') 
      errno = 5 
      filename = None 
      strerror = 'Access is denied'

C:\Moin\MoinMoin\wikiutil.py in pagediff(pagename='TermDictionary', oldpage='TermDictionary.1060182527', **kw={'ignorews': 0}) 
  458         "page": page_file,
  459     }
  460     diff = util.popen(cmd, "r")
       diff = undefined, global util = <module 'MoinMoin.util' from 'C:\Moin\MoinMoin\util\__init__.pyc'>, global popen = undefined, cmd = r'diff -u data\backup\TermDictionary.1060182527 data\text\TermDictionary'
The MoinMoin FAQ says I need to put the diff executable in my webserver's PATH, which seems to be different from my %PATH% env var in command prompt. Any idea where I can put the diff.exe or specify the webserver PATH to run this?