My IT skills are a bit outdated, still using Visual Basic and MS Access ... not good

I would like to use your Sencha Architect to develop simple web based database application for small businesses.
I downloaded a trial version of Sencha to see if I can learn to use it ...

I followed the introduction notes ... created the "CarListings" Models ... however when I try to "load data" to the "CarDataStore", I get an error 404.3 ... I'm stuck and can't go any further ...can anyone help.
I am using Windows 7 professional SP1, "IIS" as web server, Java 7 update 6, Google Chrome....
I am able to preview the projects (web server seems to be OK??), but I can't open "cars.json".

Any suggestions would be appreciated.