Errore funzione

[Luca_000]

Uff è da 2 giorni che sto provando a risolvere questo errore... ma niente da fare... praticamente un amico (tedesco) mi ha dato un file .php che dovrebbe inserire in tutti i blog (basati su wordpress) dei banner.... ma mi da questo errore

Fatal error: Call to undefined function: get_ads() in /var/www/vhosts/ilblog.it/httpdocs/wp-inst/wp-content/mu-plugins/tk_ads.php on line 123

La riga 123 è

$ads = get_ads(); 

e fa parte della funzione

    function action_display_ads() {
        $ads = get_ads();
    } 

Se volete vi posto tutto il file... anzi lo posto

class TK_ads {
    var $version = "20051017";
    var $db_version = "20051017"; //may differ from $version !
    var $settings;
    
function get_ads() {
        if (empty($this->ads)) {
        global $wpdb;
        $query = "SELECT * from `" . $wpdb->tk_ads_types . "`";
        $this->ads = $wpdb->getVar($query);
        }
        return $this->ads;    
    }
    
    function TK_ads() {
        global $wpdb;
        $this->wpdb_tables();
        add_action('admin_menu', array(&$this, 'admin_menu'));
        add_action('admin_footer', array(&$this, 'admin_footer'));
        $this->settings = get_settings('tk-ads');
        
        
        if( empty($this->settings)
            || $wpdb->get_var("show tables like '".$wpdb->tk_ads."'" ) != $wpdb->tk_ads
            || $wpdb->get_var("show tables like '".$wpdb->tk_ads_types."'" ) != $wpdb->tk_ads_types) {
            $this->make_tables();
        }
        else if ($this->settings['table_version'] != $this->table_version) {
            $this->make_tables();
            $this->added_tables = true;
        }
    }
    
    
    
    function admin_footer() {
        update_option('tk-ads', $this->settings);
    }
    
    
    function admin_menu() {
        $pfile = basename(dirname(__FILE__)) . '/' . basename(__FILE__);
        add_submenu_page('edit.php', __('Advertisement'), __('Advertisement'), 0, $pfile, array(&$this, 'plugin_content'));
    }
    
    
    function wpdb_tables() {
        global $wpdb, $table_prefix;

        $wpdb->tk_ads  = "tk_ads";
        $wpdb->tk_ads_types  = "tk_ads_types";
    }

    
    function make_tables() {
        global $wpdb, $table_prefix;
        if(!include_once(ABSPATH . 'wp-admin/upgrade-functions.php')) {
            die(_e('There is was error adding the required tables to the database.  Please refer to the documentation regarding this issue.', 'tk_ads'));
        }
        $query = "CREATE TABLE " . $wpdb->tk_ads . " (
            ad_id int(11) NOT NULL,
            theme_name varchar(255) NOT NULL,
            PRIMARY KEY (ad_id)
            );";
        $wpdb->query( $query );
        $query = "CREATE TABLE " . $wpdb->tk_ads_types . " (
            ad_id int(11) NOT NULL auto_increment,
            name CHAR(63) NOT NULL,
            content TEXT NOT NULL DEFAULT '',
            PRIMARY KEY  (ad_id)
            );";
        $wpdb->query( $query );

        $this->settings['table_version'] = $this->table_version;
        update_option('tk-ads', $this->settings);
    }

    function plugin_content() {
    
        global $wpdb;
        $action = 'display';
        if (isset($_GET['action']))
            $action = $_GET['action'];
        
        // to split up the actions we use several methods for them. looks nicer
        if (method_exists($this, 'action_'.$action))
            call_user_method('action_'.$action, $this);
    }
        
    function action_display() {
        $this->action_display_ads();
        $this->action_display_themes();
    }
    
    
    function action_display_ads() {
        $ads = get_ads();
    }
    
    function action_display_themes() {
        $themes =  array_values(get_themes());
        $ads = $this->get_ads();
        $background_colors = array('#FFFFFF', '#EEEEEE', '#DDDDDD');

        // assume there's at least one theme...
        printf('<div class="wrap">
<table class="themes">
    <tr>
        <th>'.__('Theme').'</th>
        <th>'.__('Description').'</th>
        <th>'.__('Advertisement').'</th>
    </tr>
');
        for ($i=0; $i < count($themes); $i++) {
            printf('
    <tr style="background-color:%s;">
        <td>%s</td>
        <td>%s</td>
        <td>%s</td>
    </tr>
        ', $background_colors[$i % count($background_colors)],
            $themes[$i]['Name'],
            $themes[$i]['Description'],
            $this->html_select($ads, "themes[".$themes[$i]['Name']."]", 
                                                 $ads[$themes[$i]['Name']])
            );
        }
        printf("\n\n</table>\n\n</div>");
    }
    
    
    

    
    function html_select(&$options, &$default) {
        
    }
}



$tk_ads = new TK_Ads(); 

Non so piu dove sbattere la testa... a questo tipo non riesco piu a contattarlo...
Riuscite ad aiutarmi? Grazie molte