I found a solution for my problem of not be able to use the 'browse for files'.
The problem in my case is the PHP version.
The connector is using the $_GET and $_POST. Because the server where my files are on in still using a version prior to 4.1.0 I have to use the $HTTP_GET_VARS and the $HTTP_POST_VARS.
The following lines I've added to connector.php (FCKeditor\editor\filemanager\browser\default\connectors\php)
in the DoResponse function (line 58).
global $HTTP_POST_VARS, $HTTP_GET_VARS;
if (!isset($_SERVER))
{
$_GET = &$HTTP_GET_VARS;
$_POST = &$HTTP_POST_VARS;
}
Above these lines:
if ( !isset( $_GET['Command'] ) || !isset( $_GET['Type'] ) || !isset( $_GET['CurrentFolder'] ) ) return;
I've just checked if I could browse my images and it works.
I will now test the other features like uploading.
I'm not a great progammer. Perhaps the code should go elsewhere. It should be nice if it could come in the next release 
Paul