Publishing Lightswitch App to Sharepoint 2013

Hello,

Somehow I managed to get a LightSwitch HTML5 App (Visual Studio 2013) up and running on our sharepoint test-farm (not perfectly, as there are still some error messages on debug). Now I need the Sharepoint CSOM-Api to recognize users in the app to perform access-control. I am calling the CSOM with the following script in the LS-App (screen.created method):

var scriptloc = sphosturl + "/_layouts/15/";

 $.getScript(scriptloc + "SP.Runtime.js", function () {       
            $.getScript(scriptloc + "SP.js", function () {
                SP.ClientContext();              
                getUser(screen);

            });
        });

Using firebug I get the following error messages though:

both 401 not found.  I get these messages even without adding any code, deploying an empty app. It seems Sharepoint doesnt get the mapping right or something. these files don't exist on the server I deployed the app to. There is only msls.lang-en-us.resjson

and another one, when trying to fetch active (windows  auth) user through CSOM:

Sys.InvalidOperationException: Sys.InvalidOperationException: Cannot find current web URL information on the page. from sp.js

Why does sharepoint 2013 seem to incorrectly map json files and how could I get user-recognition working with sharepoint-csom and windows/domain-authentication?

Thank you

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edit: 

when using SP.ClientContext().get_current(); which seems more appropriate I get the same error.