"Plugin could not be activated because it triggered a fatal error." Wp table reloade

Fatal error: Call to undefined function: plugin_dir_path() in /home/content/l/a/r/xxxxxxxx/html/wp-content/plugins/wp-table-reloaded/wp-table-reloaded.php on line 43

I use the exact same script on another site, and it works grate. What`s the deal?

Here`s the script..


<?php
/**
* WordPress plugin "WP-Table Reloaded" main file, responsible for initiating the plugin
*
* @package WP-Table Reloaded
* @author Tobias B&auml;thge
* @version 1.6
*/

/*
Plugin Name: WP-Table Reloaded
Plugin URI: http://tobias.baethge.com/wordpress-plugins/wp-table-reloaded-english/
Description: This plugin allows you to create and easily manage tables in the admin-area of WordPress. A comfortable backend allows an easy manipulation of table data. You can then include the tables into your posts, on your pages or in text widgets by using a shortcode or a template tag function. Tables can be imported and exported from/to CSV, XML and HTML.
Version: 1.6
Author: Tobias B&auml;thge
Author URI: http://tobias.baethge.com/
Author eMail:
Text Domain: wp-table-reloaded
Domain Path: /languages
Donate URI: http://tobias.baethge.com/donate/
*/

/* Copyright 2009 Tobias B&auml;thge

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License (GPL v2) only.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/

/**
* Define certain plugin variables as constants
*/
if ( !defined( 'WP_TABLE_RELOADED_ABSPATH' ) )
define( 'WP_TABLE_RELOADED_ABSPATH', plugin_dir_path( __FILE__ ) );
if ( !defined( 'WP_TABLE_RELOADED_BASENAME' ) )
define( 'WP_TABLE_RELOADED_BASENAME', plugin_basename( __FILE__ ) );
if ( !defined( 'WP_TABLE_RELOADED__FILE__' ) )
define( 'WP_TABLE_RELOADED__FILE__', __FILE__ );
if ( !defined( 'WP_TABLE_RELOADED_PLUGIN_VERSION' ) )
define( 'WP_TABLE_RELOADED_PLUGIN_VERSION', '1.6' );

/**
* Decide whether admin controller or frontend controller is loaded
*/
if ( is_admin() ) {
include_once( WP_TABLE_RELOADED_ABSPATH . 'controllers/controller-admin.php' );
$WP_Table_Reloaded_Admin = new WP_Table_Reloaded_Controller_Admin();
} else {
include_once ( WP_TABLE_RELOADED_ABSPATH . 'controllers/controller-frontend.php' );
$WP_Table_Reloaded_Frontend = new WP_Table_Reloaded_Controller_Frontend();

/**
* Add template tag function for "table" shortcode to be used anywhere in the template
*
* This function provides a possibility to show a table anywhere in a WordPress template,
* which is needed for any region of a theme that can not use Shortcodes.
* Thus, the function is only available in the frontend part of WordPress.
*
* @uses $WP_Table_Reloaded_Frontend
* @param string $table_query Query string like list of parameters for Shortcode "table" rendering
*/
function wp_table_reloaded_print_table( $table_query ) {
global $WP_Table_Reloaded_Frontend;
parse_str( $table_query, $atts );
echo $WP_Table_Reloaded_Frontend->handle_content_shortcode_table( $atts );
}

/**
* Add template tag function for "table-info" shortcode to be used anywhere in the template
*
* This function provides a possibility to show table info data anywhere in a WordPress template,
* which is needed for any region of a theme that can not use Shortcodes.
* Thus, the function is only available in the frontend part of WordPress.
*
* @uses $WP_Table_Reloaded_Frontend
* @param string $table_query Query string like list of parameters for Shortcode "table-info" rendering
*/
function wp_table_reloaded_print_table_info( $table_query ) {
global $WP_Table_Reloaded_Frontend;
parse_str( $table_query, $atts );
echo $WP_Table_Reloaded_Frontend->handle_content_shortcode_table_info( $atts );
}

}

?>

 

Still having the same problem..