The "Collector" web interface for building greenstone collections allows
you to specify files starting with "http://", "ftp://", or "file://" URIs.

While the "file://" is for files local to the computer that the
greenstone server is running on, http: and ftp: can be used to get files
from your network or the internet.

I'm not sure how the windows libraries handle things, but you might
possibly even be able to use windows networking style path names...
eg "file://\\servername\share\filename"
This is just a possibility though, I'm guessing. But ftp and http
definitely work.

(Also, because Microsoft inexplicibly chose to use "\" for path names,
you might need to "escape" them, eg
"file://\\\\servername\\share\\filename")

Hope this helps
John McPherson