Sounds to me that your apache isn't running. You can also try simply attaching to http://127.0.0.1
in case localhost isn't redirected to loopback for whatever reason. If that still doesn't work, check your lamp console (assuming they have one), or check your services to make sure that the apache is running.
file:// is pretty much useless. It works for .html since the browser knows how to interpret .html files. You need to go through http in order to interact at a server level.