" Apart from special processing specified for some files or file types
(extensions), the server just sends the document back in a response under
http headers (some of which may be chosen based on extension - MIME type
association in the server's config files.

I suspect that it is this part that is going wrong, there is no association
for a .ez extension and the server is responding with a 404 error. Hence the
request for a MIME type.

Jeff