Google Appengine Hello World gets HTTP 500 Error

I created a new project in Google Appengine but when I try to access it through localhost I get a HTTP 500 Error. My browser says 'localhost is currently unable to handle this request.' The following is my code for the new project:

app.yaml:

application: hello-world
version: 1
runtime: python27
api_version: 1
threadsafe: yes

handlers:
- url: /favicon.ico
  static_files: favicon.ico
  upload: favicon.ico

- url: .*
  script: main.app

libraries:
- name: webapp2
  version: "2.5.2"

main.py:

#!/usr/bin/env python
#
# Copyright 2007 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
import webapp2

class MainHandler(webapp2.RequestHandler):
    def get(self):
        self.response.write('Hello world!')

app = webapp2.WSGIApplication([
    ('/', MainHandler)
], debug=True)

When I run the following command on command line:

python "C:Program Files (x86)Googlegoogle_appenginedev_appserver.py" "C:UsersJasonDesktopHello Worldhello-world"

I get the error

  import webapp2

ImportError: No module named webapp2

INFO     2016-06-18 15:29:37,092 module.py:788] default: "GET / HTTP/1.1" 500 -