Not resolved yet…
How’s following code
add_action( 'admin_notices', create_function( '', 'echo "<div class=\"error\"><p>" . sprintf( "Rating-Widget is not activated yet. You need to <a class=\"button\" href=\"%s\">activate the account</a> to start seeing the ratings.", "edit.php?page=' . WP_RW__ADMIN_MENU_SLUG . '" ) . "</p></div>";' ) );