title: Jupyter Notebook 500 : Internal Server Error
body: <p>I want to learn how to use Jupyter Notebook. So far, I have managed to download and install it (using pip), but I'm having trouble opening it.</p>
  
  <p>I am opening it by typing:</p>
  
  <pre><code>jupyter notebook
  </code></pre>
  
  <p>in my terminal. It opens in my browser, with the URL:</p>
  
  <pre><code>http://localhost:8888/tree
  </code></pre>
  
  <p>and I just get a big:</p>
  
  <pre><code>500 : Internal Server Error
  </code></pre>
  
  <p>message. Could someone point me in the right direction of what's going wrong please?</p>
  
  <p>The full error message in my terminal:</p>
  
  <pre><code>[E 17:53:52.034 NotebookApp] Uncaught exception GET /tree (::1)
      HTTPServerRequest(protocol='http', host='localhost:8888', method='GET', uri='/tree', version='HTTP/1.1', remote_ip='::1', headers={'Accept-Language': 'en-US,en;q=0.8,es;q=0.6', 'Accept-Encoding': 'gzip, deflate, sdch', 'Host': 'localhost:8888', 'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8', 'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.112 Safari/537.36', 'Connection': 'keep-alive', 'Upgrade-Insecure-Requests': '1'})
      Traceback (most recent call last):
        File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/tornado/web.py", line 1443, in _execute
          result = method(*self.path_args, **self.path_kwargs)
        File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/tornado/web.py", line 2800, in wrapper
          return method(self, *args, **kwargs)
        File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/notebook/tree/handlers.py", line 50, in get
          terminals_available=self.settings['terminals_available'],
        File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/notebook/base/handlers.py", line 302, in render_template
          template = self.get_template(name)
        File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/notebook/base/handlers.py", line 298, in get_template
          return self.settings['jinja2_env'].get_template(name)
        File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/Jinja2-2.6-py2.7.egg/jinja2/environment.py", line 719, in get_template
          return self._load_template(name, self.make_globals(globals))
        File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/Jinja2-2.6-py2.7.egg/jinja2/environment.py", line 693, in _load_template
          template = self.loader.load(self, name, globals)
        File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/Jinja2-2.6-py2.7.egg/jinja2/loaders.py", line 127, in load
          code = environment.compile(source, name, filename)
        File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/Jinja2-2.6-py2.7.egg/jinja2/environment.py", line 493, in compile
          self.handle_exception(exc_info, source_hint=source)
        File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/notebook/templates/tree.html", line 8, in template
          data-base-url="{{base_url | urlencode}}"
      TemplateAssertionError: no filter named 'urlencode'
  [E 17:53:52.819 NotebookApp] {
        "Accept-Language": "en-US,en;q=0.8,es;q=0.6",
        "Accept-Encoding": "gzip, deflate, sdch",
        "Host": "localhost:8888",
        "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8",
        "User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.112 Safari/537.36",
        "Connection": "keep-alive",
        "Upgrade-Insecure-Requests": "1"
      }
  [E 17:53:52.819 NotebookApp] 500 GET /tree (::1) 874.29ms referer=None
  </code></pre>
  
  <hr>
  
  <p>EDIT</p>
  
  <p>When attempting to update ipython as advised, the following error message was produced:</p>
  
  <pre><code>Exception:
  Traceback (most recent call last):
    File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip/basecommand.py", line 209, in main
      status = self.run(options, args)
    File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip/commands/install.py", line 317, in run
      prefix=options.prefix_path,
    File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip/req/req_set.py", line 732, in install
      **kwargs
    File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip/req/req_install.py", line 835, in install
      self.move_wheel_files(self.source_dir, root=root, prefix=prefix)
    File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip/req/req_install.py", line 1030, in move_wheel_files
      isolated=self.isolated,
    File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip/wheel.py", line 247, in move_wheel_files
      prefix=prefix,
    File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pip/locations.py", line 142, in distutils_scheme
      i = d.get_command_obj('install', create=True)
    File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/distutils/dist.py", line 845, in get_command_obj
      klass = self.get_command_class(command)
    File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/setuptools/dist.py", line 430, in get_command_class
      self.cmdclass[command] = cmdclass = ep.load()
    File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pkg_resources/__init__.py", line 2229, in load
      return self.resolve()
    File "/opt/local/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/pkg_resources/__init__.py", line 2235, in resolve
      module = __import__(self.module_name, fromlist=['__name__'], level=0)
  ImportError: No module named command.install
  </code></pre>