register_activation_hook geht nicht!

// Install the needed database table
function google_routeplaner_install() {
    global $wpdb, $table_prefix;
    $tables = $wpdb->get_col('SHOW TABLES');
    if (!in_array($table_prefix . 'google_routeplaner', $tables)) {
    
        $charset_collate = '';
        if ( version_compare(mysql_get_server_info(), '4.1.0', '>=') ) {
            if (!empty($wpdb->charset)) {
                $charset_collate .= sprintf(' DEFAULT CHARACTER SET %s', $wpdb->charset);
            }
            if (!empty($wpdb->collate)) {
                $charset_collate .= ' COLLATE $wpdb->collate';
            }
        }
        $sql_routeplaner = 'CREATE TABLE `' . $table_prefix . 'google_routeplaner` (
                     `planer_id` INT NOT NULL AUTO_INCREMENT,
                     `start_location` VARCHAR(120) NOT NULL,
                     `planer_width` INT,
                     `planer_height` INT,
                     `planer_type` VARCHAR(120) NOT NULL,
                     `planer_zoom_control` VARCHAR(120) NOT NULL,
                     `planer_type_control` VARCHAR(120) NOT NULL,
                     `planer_overview` VARCHAR(3) NOT NULL,
                     PRIMARY KEY (`planer_id`)
                     )%s';
        $wpdb->query(sprintf($sql_routeplaner, $charset_collate));
    }
}


// Install
if ( function_exists('register_activation_hook') )
    register_activation_hook(__FILE_, 'google_routeplaner_install');