[PHP] A Newbie needs help with his first Class

[Don]

Hi,

I'm trying to write my first class.  Here is the code contained in a file called 
"globals.php":

<?PHP
class Globals
{
  var $gDISPLAY  = 1;        /* Display graphic - no rollover */
  var $gROLLOVER = 2;     /* Display graphic with rollover */
  var $root_path;                /* Path to document root directory */
  var $relative_path;            /* Path from document root to relative root directory 
*/

  function Globals($start_dir)
  {
    if ( strlen($DOCUMENT_ROOT) == 0) {
       $this->$root_path = "/";
    } else {
       $this->$root_path = $DOCUMENT_ROOT;
    }
    $this->$relative_path = $this->$root_path . $start_dir;
  }
}

$global = new Globals("/staging_area/phase-2/");
?>


Within my html page, I am tesing the class by trying the following:
<?php
require("globals.php");
echo $global->root_path . "<br>";
echo $global->relative_path . "<br>";
?>

However, nothing is being written to my browser.  Is there a problem with the code?

Thanks,.
Don