Aaaaahhh..  Error message 404 but it’s there…

According to Microsoft kb326965, IIS 6.0 does not serve unknown MIME types.  So if you are running MS Server 2003, you may experience this problem.

Basically, the IIS webserver doesn’t recognise the type of file and won’t give it to you, hence the 404 (not found).

You can manually add MIME types to IIS by:
-Select the properties of the Webserver via the IIS console
-click MIME Types
-click New

-enter the new file extensions:
     [ .xlsx
        application/vnd.spreadsheetml.sheet ]

-restart IIS when finished (needed to rebuild MetaBase.xml)

List of MIME TYPES for Office 2007

application/vnd.wordprocessingml.document docx
application/vnd.wordprocessingml.template dotx
application/vnd.presentationml.template potx
application/vnd.presentationml.slideshow ppsx
application/vnd.presentationml.presentation pptx
application/vnd.spreadsheetml.sheet xlsx
application/vnd.spreadsheetml.template xltx

ALSO, there was a small MediaWiki config tweak (anyone else hosting MediaWiki on IIS?)

-add file extensions to the LocalSettings.php : $wgFileExtensions  -may have to add type to $wgTrustedMediaFormats if used
-edited the \includes\mime.types (!must be done for each server)

this will show beside the file in mediawiki, if not, you will see unknown\unknown

Add MIME type to IIS