options validator input is false?

This kind of setup skeleton works for me to process the custom options page input :

<?php
/*
Plugin Name: Settings Skeleton
*/

if(!class_exists('MySettings')){    

    function call_my_settings() {
        return new MySettings();
    }

    if (is_admin()){
        add_action( 'init', 'call_my_settings' );
    }

    class MySettings{

        public function __construct(){
            add_action('admin_menu', array(&$this, 'add_menu'));
            add_action('admin_init', array(&$this,'settings') );
        }

        public function add_menu(){
            add_options_page(__('My Plugin Settings','myplugindomain'), 'My Plugin Settings', 'manage_options', __FILE__,  array(&$this,'options_page'));
        }   

        public function settings() {
            register_setting( 'my_settings', 'my_settings', array(&$this,'validate') );
        }

        public function validate($input) {
            // do validation
            $input['mytext']=esc_attr($input['mytext']);
            return $input;
        }

        public function options_page(){
        ?>
        <div class="wrap">
            <div class="icon32" id="icon-options-general"><br></div>
            <h2><?php _e('My plugin settings','myplugindomain'); ?></h2>
            <form method="post" action="options.php">
                <?php settings_fields('my_settings'); ?>
                <?php $settings = get_option('my_settings'); ?>
                <table class="form-table">
                    <tr>
                        <th scope="row" colspan="2">
                            <h3><?php _e('General settings','myplugindomain'); ?></h3>
                        </th>
                    </tr>
                    <tr>
                        <th scope="row"><?php _e('My text','myplugindomain'); ?> </th>
                            <td>
                                <input type="text" size="70" name="my_settings[mytext]" value="<?php echo $settings[mytext]; ?>" />
                             </td>
                     </tr>
                </table>
                <?php submit_button(); ?>
             </form>
         </div>
        <?php
        }
    }
}

This will give you the following options page:

How do you hook your settings() function ?

In the code example above the settings() functions is hooked into the admin_init action, i.e.

add_action('admin_init', array(&$this,'settings') );