Fatal error: Call to undefined method Gdk::screen_width()

I have the  php-gtk-2.0.0 Windows binary pack - 29-Feb-2008  installed 
with PHP 5.2.5

I am getting the error "Fatal error: Call to undefined method 
Gdk::screen_width()"

I am using code from Pro PHP-GTK by Scott Mattocks downloaded from his 
website. In any of the scripts that perform a Gdk::screen_width() I get 
the above error. I have the location of php-gtk2 in my path statement.

Please help me with this problem.

Thanks

David Hurley


One of the scripts with the problem:

<?php
/**
 * Script to run our application.
 */
class Crisscott_SplashScreen extends GtkWindow {

    // A widget to show a status message.
    public $status;

    public function __construct()
    {
        // Call the parent constructor.
        parent::__construct();

        // Turn off the window borders.
        $this->set_decorated(false);

        // Set the background color to white.
        $style = $this->style->copy();
        $style->bg[Gtk::STATE_NORMAL] = $style->white;
        $this->set_style($style);

        // Move the window to the center of the screen.
        $this->set_uposition(Gdk::screen_width() / 2, 
Gdk::screen_height() / 2);
        // Call a helper method to create the pieces of the splash screen.
        $this->_populate();

        // Set up the application to shutdown cleanly.
        $this->connect_object('destroy', array('Gtk', 'main_quit'));
    }

    private function _populate()
    {
        // Create the containers.
        $frame     = new GtkFrame();
        $hBox      = new GtkHBox();
        $vBox      = new GtkVBox();
       
        // Set the shadow type.
        $frame->set_shadow_type(Gtk::SHADOW_ETCHED_OUT);

        // Create title label.
        $titleText = '<span foreground="#000060"><b>Crisscott ' .
            'Product Information Management System</b></span>';
        $title = new GtkLabel($titleText);
        // Use markup to make the label blue and bold.
        $title->set_use_markup(true);

        // Create an initial status message.
        $this->status = new GtkLabel('Initializing Main Window');
       
        // Stack the labels vertically.
        $vBox->pack_start($title,        true, true, 10);
        $vBox->pack_start($this->status, true, true, 10);

        // Add a logo image.
        $logoImg = GtkImage::new_from_file('Crisscott/images/logo.png');

        // Put the image and the first box next to each other.
        $hBox->pack_start($logoImg, false, false, 10);
        $hBox->pack_start($vBox,    false, false, 10);

        // Put everything inside a frame.
        $frame->add($hBox);

        // Put the frame inside the window.
        $this->add($frame);
    }
   

    public function start()
    {
        $this->show_all();
        Gtk::main();
    }
}

$splash = new Crisscott_SplashScreen();
$splash->start();
/*
 * Local variables:
 * tab-width: 4
 * c-basic-offset: 4
 * End:
 */
?>