Notice: Undefined index: add_bundle and remove_all

I think there needs to be some isset conditionals wrapping the conditionals that make use of $get[] variables. I went through and fixed them, replacing the contents of the magic.php file with this code will fix the errors.

<?php /*
Plugin Name: WP Example Content
Plugin URI: https://hivemindlabs.com/projects/wp-example-content/
Description: Provides multiple example posts & pages to assist with styling and developing new and current themes.
Version: 1.3
Author: Hivemind Labs, Inc.
Author URI: https://hivemindlabs.com/

    Copyright 2011 Hivemind Labs, Inc.  (email : [email protected])

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

    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
*/

// Start up the engine
add_action('admin_menu', 'example_posts_menu');

// Define new menu page parameters
function example_posts_menu() {
	add_menu_page( 'WP Example Content', 'WP Example Content', 'activate_plugins', 'wp-example-content', 'example_posts_options', '');
}

// Define new menu page content
function example_posts_options() {

	if (!current_user_can('manage_options'))  {
		wp_die( __('You do not have sufficient permissions to access this page.') );
	} else {

		?>

    <!-- Output for Plugin Options Page -->
	<div class="wrap">
        <h2 id="">Example Post Generator</h2>

				<?php if (isset($_GET["add_bundle"])) {
        	if ($_GET["add_bundle"] == true){ ?>
            <div class="updated below-h2" id="message">
                <p>Example Post Bundle Added!</p>
            </div>
        <?php } } ?>
				<?php if (isset($_GET["remove_all"])) {
				 if ($_GET["remove_all"] == true){;?>
            <div class="updated below-h2" id="message">
                <p>All Example Posts Removed!</p>
            </div>
        <?php } } // endif ?>

        <p>Welcome to the WP Example Content! With the options below, you can add and remove example post content to assist you in designing and developing new and current themes. Enjoy!</p><br>

        <h3 id="">Add A Bundle Of Example Posts</h3>
        <p>Here, you can add the complete bundle of example posts & pages. These posts are:</p>
        <ol>
            <li>Multiple Paragraph Posts</li>
            <li>Image Post</li>
            <li>UL and OL Post</li>
            <li>Blockquote Post</li>
            <li>Post with links</li>
            <li>Post with Header tags H1 through H5</li>
        </ol>
		<p>In addition to the example posts, the bundle includes 5 pages, a child page, and a grandchild page, to assist with styling menus and navigation.</p>
        <a href="?page=wp-example-content&add_bundle=true" class="button">Add Bundle of Sample Posts</a>
        <br><br><br>

        <h3 id="">Remove All Posts</h3>
        <p>Here, you can remove all example posts that you've created with the plugin, in one fell swoop. That easy? Oh yeah.</p>
        <a href="?page=wp-example-content&remove_all=true" class="button">Remove All Sample Posts</a>
	</div>
	<!-- End Output for Plugin Options Page -->

<?php

	// Add Posts -------------------------
	if (isset($_GET["add_bundle"])) {
		if ($_GET["add_bundle"] == true){
			global $wpdb;
			// Get content for all posts and pages, then insert posts
			include 'content.php';
			foreach ($add_posts_array as $post){
				wp_insert_post( $post );
			};

			// Add Child Page
			$page_name = 'Image Page';
			$page_name_id = $wpdb->get_results("SELECT ID FROM " . $wpdb->base_prefix . "posts WHERE post_title = '". $page_name ."'");
			foreach($page_name_id as $page_name_id){
				$imagepageid = $page_name_id->ID;
				include 'content.php';
				wp_insert_post( $childpage );
			};

			// Add Grandchild Page
			$page_name = 'Child Page';
			$page_name_id = $wpdb->get_results("SELECT ID FROM " . $wpdb->base_prefix . "posts WHERE post_title = '". $page_name ."'");
			foreach($page_name_id as $page_name_id){
				$childpageid = $page_name_id->ID;
				include 'content.php';
				wp_insert_post( $grandchildpage );
			};
		};
	};
	// ---------------------------------------

	//  Remove Posts -------------------------
	if (isset($_GET["remove_all"])) {
		if ($_GET["remove_all"] == true){
			// Get content for all posts and pages, then remove them
			include 'content.php';
			foreach($remove_posts_array as $array){
				$page_name = $array["post_title"];
				global $wpdb;
				$page_name_id = $wpdb->get_results("SELECT ID FROM " . $wpdb->base_prefix . "posts WHERE post_title = '". $page_name ."'");
				foreach($page_name_id as $page_name_id){
					$page_name_id = $page_name_id->ID;
					wp_delete_post( $page_name_id, true );
				};
			};
		};
	};
	// ---------------------------------------

}}; ?>