The correct content type for JSON is application/json, not application/x-javascript BTW...
Generally the Mime map in IIS only is important for file extension mappings. If you have a static file served with an unknown extension that isn't in the mime list IIS throws a 404.3.
I've written a WC page that generates a JSON file used to populate a Google map. I'm running it on my localhost under Win7. The script map and page are displaying fine but the jQuery code that is trying to load the JSON file is returning an error. When I try and access the JSON file from the browser address box, I get the 404.3 error yet when I try and use the physical address the data file loads and displays without any problem.
I have tried in both IE9 and Chrome 23.x. The error page suggests there is something wrong with MIME type or a Handler that is not configured correctly.
SOLUTION: Open IIS Configuration and scroll down to MIME Types. Double click to open and after double checking discovered JSON was not listed. After right clicking and selecting ADD, I entered the extentsion JSON and the application type as "application/x-javascript". This has fixed the problem for my localhost.
I just wonder if there is going to be a similar problem for client browsers who will be loading my pages over the Internet or if this is just a Intranet issue... time or someone much wiser <g> will tell!
--hm
PS - thanks for changing the icon to "new message", it almost got me again!<s>