xymalf on "how do I write the function to open the page?"

<?php

/*
Plugin Name: Menu Test
Plugin URI: http://codex.wordpress.org/Adding_Administration_Menus
Description: Menu Test
Author: Codex authors
Author URI: http://example.com

warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'boj_menuexample_settings_page' not found or invalid function name in C:\wamp\www\WPDev\wp-includes\plugin.php on line 470
*/

add_action( 'admin_menu', 'boj_menuexample_create_menu' );

function boj_menuexample_create_menu() {

add_menu_page( 'My Plugin Settings Page', 'Menu Example Settings','manage_options', _FILE_, 'boj_menuexample_settings_page', plugins_url( '/images/wp-icon.png', _FILE__));

}

add_action( 'about_menu', 'boj_menuexample_about_page');
function boj_menuexample_about_page() {
add_submenu_page( _FILE_, 'About My Plugin', 'About', 'manage_options',_FILE_.'_about', boj_menuexample_about_page);

}

add_action( 'uninstall_menu', 'boj_menuexample_uninstall_page');
function boj_menuexample_uninstall_page() {

add_submenu_page( _FILE_,'Uninstall My Plugin', 'uninstall', 'manage_options',
_FILE_.'_uninstall', boj_menuexample_uninstall_page);

}

?>