Running v 7 on Windows 2000 server.
Configured attachment directory and full path correctly, privileges for the web server user set correctly ("test directory" can create a file in the attachments folder).

The file manager allows to add/remove files.
Links to the attachments show up in the posts.
No error messages or anything.

However:

Clicking on a link leads to a "page not found" error message.
The URL is correct, and the file name shown is the name of the file I have "uploaded" via the file manager.

But the file is not created in the attachments folder.

When I replace the file name in the URL with the name of a file that exists in the attachment folder, it works.