title: Proxy Authentication Required NLTK download
body: <p>I have installed python 2.7.3 on a Windows 8, 64 bit machine, sublime text and nltk 3.0.1 with the following steps:</p>
  
  <ul>
  <li><p>Install Setuptools:
  <a href="http://pypi.python.org/pypi/setuptools" rel="nofollow noreferrer">http://pypi.python.org/pypi/setuptools</a> and run ez_setup.py from the directory stored in python27 (from CMD prompt)</p></li>
  <li><p>Install NLTK: <a href="http://pypi.python.org/pypi/nltk" rel="nofollow noreferrer">http://pypi.python.org/pypi/nltk</a>
  In nltk directory run setup.py to install nltk (from CMD prompt)</p></li>
  <li><p>Change the environmental variables to %PYTHONPATH%;C:\Python27;C:\Python27\DLLs;C:\Python27\Lib;C:\Python27\Lib\lib2to3;C:\Python27\Scripts with PYTHONPATH with C:\Python27</p></li>
  </ul>
  
  <p>Test installation: Start>Python34, then type import nltk
  in sublime type</p>
  
  <pre><code>import nltk
  nltk.set_proxy('xxx.xx.xx.xx:yy',('username','pwd'))
  nltk.download()
  </code></pre>
  
  <p>However, I am met with the following error:</p>
  
  <pre><code>HTTP Error 407: Proxy Authentication Required (The ISA Server requires   authorization to fulfill the request. Access to the Web Proxy Filter is denied.
  </code></pre>
  
  <p>Despite giving the proxy details why am I getting this error?</p>
  
  <p>Please help,
  Arc.</p>