Ionic build WP7 fails

I cant get the build of a WP7 app to work anymore. It has worked before but then I did update some npm packages and it didnt work anymore although I did downgrade the cordova package again to the point where WP7 was still available. Everytime I build the app it gives me this error:

 Error: C:\Users\xy\Apps\xApp\platforms\wp7\cordova\build.bat: Command
 failed with exit code 2
 at ChildProcess.whenDone (C:\Users\xy\AppData\Roaming\npm\node_modules\cor
 dova\node_modules\cordova-lib\src\cordova\superspawn.js:131:23)
    at ChildProcess.emit (events.js:98:17)
    at maybeClose (child_process.js:755:16)
    at Process.ChildProcess._handle.onexit (child_process.js:822:5)

I can't figure out why it isnt working anymore. Does anyone have any idea?

thanks in advance