title: Error loading IPython notebook
body: <p>Once I opened a notebook file with Jupyter (it asks me to convert the file) I never can open it in the standard IPython notebook anymore. I get the following error:</p>
  
  <pre><code>Error loading notebook
  Bad Request
  
  2014-12-21 04:13:03.203 [NotebookApp] WARNING | Unreadable Notebook: /FunIT experiment.ipynb global name  'NBFormatError' is not defined
  WARNING:tornado.access:400 GET /api/notebooks/FunIT%20experiment.ipynb?_=1419153182928 (::1) 3.11ms referer=http://localhost:8888/notebooks/FunIT%20experiment.ipynb
  </code></pre>
  
  <p>An example of such corrupted files is this one:
  <a href="https://www.dropbox.com/s/7io99wpoivxmc8f/FunIT%20experiment.ipynb?dl=0">https://www.dropbox.com/s/7io99wpoivxmc8f/FunIT%20experiment.ipynb?dl=0</a></p>
  
  <p>How can I revert this process? I need to open these files with the standard IPython notebook (v2.2.0).</p>