title: Jupyter Notebook Extensions Fail to Load
body: <p>I am running Ubuntu 14.04 in virtual box with a recent anaconda install. I installed jupyter notebooks using conda. I have followed all of the documentation that I can find online to install notebook extensions but they fail to load with the error messages listed below. The first error is from the jupyter notebook app running in a terminal and the second error is in the chrome java console. Notice that I cannot post this question with this many hyperlinks so I remove the "p" from "http" in my error messages. </p>
  
  <blockquote>
    <p>[W 07:02:06.451 NotebookApp] 404 GET
    /nbextensions/python-markdown.js?v=20150904070147 (127.0.0.1) 8.47ms
    referer=htt://localhost:8888/notebooks/Untitled.ipynb</p>
    
    <p>htt://localhost:8888/nbextensions/python-markdown.js?v=20150904070147
    Failed to load resource: the server responded with a status of 404
    (Not Found)</p>
  </blockquote>
  
  <p>To detail my installation method: I cloned the git repository <code>[IPython-notebook-extensions][1]</code> and used the command <code>jupyter-nbextension install python-markdown</code> inside the <code>IPython-notebook-extensions/usability/</code> folder. I then enabled the extension with <code>jupyter-nbextension enable python-markdown</code>. I ran these commands as superuser as well.</p>
  
  <p>After this failed I installed this extension inside python (from the usability/ directory of the repository) using:</p>
  
  <pre><code>import notebook
  notebook.install_nbextension('python-markdown',user=True)
  E=notebook.nbextensions.EnableNBExtensionApp()
  E.enable_nbextension('python-markdown')
  </code></pre>
  
  <p>I also tried this as the superuser without the parameter <code>user=True</code>.</p>
  
  <p>I have confirmed that the files copied to both <code>/usr/local/share/jupyter/nbextensions/python-markdown</code> and <code>~/.local/share/jupyter/nbextensions/python-markdown</code>. The extension is enabled in the ~/.jupyter/nbconfig/notebook.json file. Finally, I also deleted the chromium and mozilla cache (by deleting the folders in the <code>~/.cache</code> directory) multiple times while trying this.</p>