flex form submission

Question

Your function would look like this: submitForm():void { var req:URLRequest = new URLRequest("http://localhost/c/x.php"); req.method = URLRequestMethod.POST; var vars:URLVariables = new URLVariables(); vars.yourVar = 'yourValue'; req.data = vars; var ldr:Loader = new Loader(); ldr.load(req); }

("Error #2044: Unhandled IOErrorEvent:. text=Error #2124: Loaded file is an unknown type")

i wrote action script as above i want to load php file from a page by posting a set of inputs from a form that was developed in adobe flex.by giving the above code it is telling loader file has unknown type.how to load php file?