My install activation hook:

function mouldings_activate() {
    global $wpdb, $mouldings_options;
    if( false == get_option( 'mouldings_settings' ) ) {
        $mouldings_options = array(
            'img_base64_enable'         => '1',
            'moulding_combination_page' => '',
            'moulding_collection_page'  => '',
            'idea_gallery_thumb_height' => '200',
            'idea_gallery_thumb_width'  => '200',
            'collection_thumb_height'   => '200',
            'collection_thumb_width'    => '200',
            'profile_item_columns'      => '4',
            'idea_item_columns'         => '2',
            'collections_item_columns'  => '2',
            'combinations_item_columns' => '4',
            'profile_element_order' => array(
                'Option 1',
                'Option 2',
                'Option 3',
                'Option 4',
                'Option 5'
            )
        );
        update_option( 'mouldings_settings', $mouldings_options );
    }
}
register_activation_hook( MOULDINGS_PLUGIN_FILE, 'mouldings_activate' );

mouldings_settings output (in wp_options table):

a:12:{s:17:"img_base64_enable";s:1:"1";s:25:"moulding_combination_page";s:0:"";s:24:"moulding_collection_page";s:0:"";s:25:"idea_gallery_thumb_height";s:3:"200";s:24:"idea_gallery_thumb_width";s:3:"200";s:23:"collection_thumb_height";s:3:"200";s:22:"collection_thumb_width";s:3:"200";s:20:"profile_item_columns";s:1:"4";s:17:"idea_item_columns";s:1:"2";s:24:"collections_item_columns";s:1:"2";s:25:"combinations_item_columns";s:1:"4";s:21:"profile_element_order";a:5:{i:0;s:8:"Option 1";i:1;s:8:"Option 2";i:2;s:8:"Option 3";i:3;s:8:"Option 4";i:4;s:8:"Option 5";}}

Trying to get value of 'profile_element_order' in table list:

$count = 0;
foreach($mouldings_options['profile_element_order'] as $key => $item) :
    echo '<tr id="list_items_' . $key . '" class="list_item">';
        echo '<td>' . $item . '</td>';
        echo '<td>' . $count . '</td>';
    echo '</tr>';
    $count++;
endforeach;

Getting this error: Notice: Undefined index: profile_element_order in /wp-content/plugins/mouldings/includes/plugin-settings.php on line 234 (which is the foreach call)