title: File not found error, but file exists
body: <p>I am working on a simple webapp from Head First Python. I am using ubuntu 14.04. But it is the error:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/usr/lib/python3.4/http/server.py", line 1143, in run_cgi
      os.execve(scriptfile, args, env)
  FileNotFoundError: [Errno 2] No such file or directory: 
  '/home/sarthak/Desktop/Learn/HeadFirstPython/chapter7/webapp/cgi-bin/generate_list.py'
  
  127.0.0.1 - - [12/Jun/2015 07:08:25] CGI script exit status 0x7f00
  </code></pre>
  
  <p>The file surely exists on the system and it is made executable.</p>
  
  <p>How to fix the problem?</p>