title: Error using netCDF4 python module
body: <p>I am using netCDF4 and python 3.4.</p>
  
  <p>I run the following line of code in order to start writing a new netCDF file that I will be filling with data later in my code following netcdf4 documentation.  I however keep getting this error...</p>
  
  <p><strong><em>File "netCDF4.pyx", line 1466, in netCDF4.Dataset.__init__ (netCDF4.c:19692) RuntimeError: Permission denied</em></strong>    </p>
  
  <pre><code>from netCDF4 import Dataset
  rootgrp = Dataset('test.nc', 'w', format='NETCDF4')
  </code></pre>
  
  <p>Any help will be most appreciated. </p>