cgi.py (or other CGI programming) doesn't work sometimes on NT or win95!
Be sure you have the latest python.exe, that you are using python.exe rather than a GUI version of Python and that you have configured the server to execute
"...\python.exe -u ..."
for the CGI execution. The -u (unbuffered) option on NT and Win95 prevents the interpreter from altering newlines in the standard input and output. Without it post/multipart requests will seem to have the wrong length and binary (e.g. GIF) responses may get garbled (resulting in broken images, PDF files, and other binary downloads failing).