我正在尝试使用在中找到的示例代码http://codex.buddypress.org/developer-docs/group-extension-api/ 在插件中使用，但当我尝试使用它时，会不断出现以下错误：

致命错误：在/home/httpd/html/wearewomenmarch中找不到类“BP\\u Group\\u Extension”。net/public\\u html/wp-content/plugins/buddypress组文档/索引。php在线53

所讨论的第53行如下：

class BP_Group_Document_List_Extension extends BP_Group_Extension {  

我尝试使用的全部代码是

class BP_Group_Document_List_Extension extends BP_Group_Extension {  
var $visibility = \'private\';
var $enable_create_step = false;
var $enable_nav_item = false;
var $enable_edit_item = false;

function bp_group_document_list_extension() {
        $this->name = \'Documents List\';
        $this->slug = \'group-document-list\';

        $this->create_step_position = 21;
        $this->nav_item_position = 31;
    }

    function create_screen() { }

    function create_screen_save() { }

    function edit_screen() {  }

    function edit_screen_save() { }

    function display() {
        display_group_document_list();
    }

    function widget_display() {  }
}
bp_register_group_extension( \'BP_Group_Document_List_Extension\' );

组在站点上处于活动状态，BP组日历插件处于活动状态。我看到它也使用了组扩展API，而且很有效，所以我肯定我犯了一些错误。如果您能给我一些建议，我将不胜感激，这样我就可以解决这个致命的错误。

/*
Plugin Name: My Plugin
Plugin URI: http://example.org/my-plugin/
Description: My BuddyPress plugin
Version: 1.0
Requires at least: WordPress 2.9.1 / BuddyPress 1.2
Tested up to: WordPress 2.9.1 / BuddyPress 1.2
License: GNU/GPL 2
Author: Some Person
Author URI: http://example.org/me/
*/

/* Only load code that needs BuddyPress to run once BP is loaded and initialized. */
function my_plugin_init() {
    require( dirname( __FILE__ ) . \'/my-plugin.php\' );
}
add_action( \'bp_include\', \'my_plugin_init\' );

/* If you have code that does not need BuddyPress to run, then add it here. */