Unable to upload an application via Google App Engine (from an Ubuntu 14.04 LTS machine)

I am just beginning to learn about the basics of web serving, and I've run into difficulty uploading an application online via the Google App Engine.

What worked without problems

My machine is running Ubuntu 14.04 LTS. First, I downloaded the Google App Engine SDK for Python which I then installed into the directory ~/Desktop/web_development/google_appengine.

Next, I implemented an application which displays a short message. Specifically, I created the directory ~/Desktop/web_development/unit_01/homework_01 in which I saved the files helloworld.py and app.yaml; these two files were created according to the instructions on http://ift.tt/1uykWNt.

After navigating into ~/Desktop/web_development, I was able to successfully test the application via the terminal command:

$ google_appengine/dev_appserver.py unit_01/homework_01/

(In other worlds, I could successfully open http://localhost:8080/ in my browser.)

Where the problem occurred:

When I run the command

$ google_appengine/appcfg.py -A ludata-rabota update unit_01/homework_01/

I receive the following output:

02:45 PM Application: ludata-rabota (was: None); version: 1 02:45 PM Host: appengine.google.com 02:45 PM Starting update of app: ludata-rabota, version: 1 02:45 PM Getting current resource limits. 02:45 PM Scanning files on local disk. Error 404: --- begin server output --- This application does not exist (app_id=u'ludata-rabota'). --- end server output ---

Feedback request

If you could offer any feedback as to how to resolve this issue, I would be very grateful.