title: ftplib.error_perm: 500 not understood downloading file from ftp
body: <p>I am newbie to python and  trying to download all csv  files from a ftp folder   but I receive this error.
   this is my code:</p>
  
  <pre><code>ftp = ftplib.FTP('192.128.0.20', 'bingo', 'Password')
  ftp.cwd('/')
  filematch = '*.csv'
  
  
  for filename in ftp.nlst(filematch):
      fhandle = open(filename,'wb')
      ftp.retrbinary('RETR' + filename, fhandle.write)
      fhandle.close()
  </code></pre>
  
  <p>this is my error:</p>
  
  <pre><code> Traceback (most recent call last):
        File "./dirmon.py", line 65, in &lt;module&gt;
          ftp.retrbinary('RETR' + filename, fhandle.write)
        File "/usr/lib/python2.7/ftplib.py", line 406, in retrbinary
          conn = self.transfercmd(cmd, rest)
        File "/usr/lib/python2.7/ftplib.py", line 368, in transfercmd
          return self.ntransfercmd(cmd, rest)[0]
        File "/usr/lib/python2.7/ftplib.py", line 331, in ntransfercmd
          resp = self.sendcmd(cmd)
        File "/usr/lib/python2.7/ftplib.py", line 244, in sendcmd
          return self.getresp()
        File "/usr/lib/python2.7/ftplib.py", line 219, in getresp
          raise error_perm, resp
      ftplib.error_perm: 500 RETRRINGGODATA-2014-07-02.CSV not understood
  </code></pre>