Firefox extensions xpi error

Have been toying with developing an extension for firefox and uploaded the file to my brinkster account.

Trying to create a web based install using the Javascript code http://developer.mozilla.org/en/docs/Installing_Extensions_and_Themes_From_Web_Pages I created a xpi file and the JavaScript. (The xpi file is just a zip file renamed). Trying to install into my firefox gave a -223 error (I think that was it).

so...trying to isolate the error....

When I upload as a .zip I can download via my web page, but when I either upload as a zip or upload as a zip and rename the file it will not download correctly.

Download the xpi file then rename as zip. Then opening gives a file corrupt error.

One possible suggestion  ( http://support.on2.com/flixpublisher/faq/) was
You are using Microsoft IIS as your webserver, but the MIME type (also called "Content-type", or "Internet Media type") for XPI files has not been added to your IIS configuration.

To fix this problem, add the following to your IIS MIME types configuration:

Extension:      .xpi
Mime Type:      application/x-xpinstall

Brinkster added this to their IIS server and all is sweet now.

So, now onto adding some JavaScript to my extension :)