title: opendir() of an ftp url fails
body: <p>I'm trying to open a folder from a distant server. I wrote :</p>
  
  <pre><code>if ($folderHandle = opendir($folder))
  </code></pre>
  
  <p>where <code>$folder = "ftp://xxx:xxx@xxx.net:21"</code></p>
  
  <p>I get the weird error <code>Warning: opendir(ftp://...:21): failed to open dir: operation failed in ... on line 38</code></p>
  
  <p>Any ideas as to where I should go from here ? Is it a problem with the FTP credentials ?</p>