How to have one and only one folder per user ?

Thank you very much for this answer, which seems to be exactly what I need. But I was trying to make it work, when I get a javscript alert about an error :
"URL requested: "http://www.studiokalafunga.com/ckfinder/core/connector/php/connector.php?command=Init"
Server response:
Status: 200
Response text:
<?xml version="1.0" encoding="utf-8"?><br />
<b>Fatal error</b>: Call to a member function getUrl() on a non-object in <b>D:\www\studiokalafunga.com\htdocs\ckfinder\core\connector\php\php5\CommandHandler\Init.php</b> on line <b>123</b><br />"

I try to revert what I did in the config file, but the error remains... Do you think it could be related to the fact I have another function called getUrl somewhere else in my code, which is not a class function ?

Thanks.

<?php

function CheckAuthentication()
{    
   return true;
}
$config['LicenseName'] = 'www.studiokalafunga.com';
$config['LicenseKey'] = '';
$baseUrl = '/fichiers/';
$baseDir = resolveUrl($baseUrl);
$config['Thumbnails'] = Array(
      'url' => $baseUrl . '_thumbs',
      'directory' => $baseDir . '_thumbs',
      'enabled' => true,
      'directAccess' => false,
      'maxWidth' => 100,
      'maxHeight' => 100,
      'bmpSupported' => false,
      'quality' => 80);
$config['Images'] = 0 ;   

$config['RoleSessionVar'] = 'CKFinder_UserRole';
      
$config['AccessControl'][] = Array(
      'role' => '*',
      'resourceType' => '*',
      'folder' => '/',

      'folderView' => true,
      'folderCreate' => true,
      'folderRename' => true,
      'folderDelete' => true,
      
      'fileView' => true,
      'fileUpload' => true,
      'fileRename' => true,
      'fileDelete' => true);   

$config['AccessControl'][] = Array(
      'role' => '*',
      'resourceType' => '*',
      'folder' => '/_thumbs',

      'folderView' => false,
      'folderCreate' => false,
      'folderRename' => false,
      'folderDelete' => false,

      'fileUpload' => false,
      'fileRename' => false,
      'fileDelete' => false);

$config['DefaultResourceTypes'] = 'files';

if ( isset($_SESSION['CKFinder_UserFolder'], $_SESSION['CKFinder_UserRole']) ) {
   $config['ResourceType'][] = Array(
         'name' => 'files',            // Single quotes not allowed
         'url' => $baseUrl . $_SESSION['CKFinder_UserFolder'],
         'directory' => $baseDir . $_SESSION['CKFinder_UserFolder'],
         'maxSize' => 0,
         'allowedExtensions' => '',
         'deniedExtensions' => 'php,php3,php5,cgi,css');
}
$config['CheckDoubleExtension'] = true;
$config['FilesystemEncoding'] = 'UTF-8';
$config['SecureImageUploads'] = true;
$config['CheckSizeAfterScaling'] = true;
$config['HtmlExtensions'] = array('html', 'htm', 'xml', 'js');
$config['HideFolders'] = Array(".svn", "CVS");
$config['HideFiles'] = Array(".*");
$config['ChmodFiles'] = 0777 ;
$config['ChmodFolders'] = 0755 ;