using rotate causes error

Hello,

Adding a single banner works fine but when i try to use the random i get issues,

<?php if(function_exists("useful_banner_manager_banners_rotation")){ useful_banner_manager_banners_rotation("1,3",7,543,102,"rand"); } ?>

that displays the image but when it goes to change nothing happens and i get the following error in firefox

ReferenceError: useful_banner_manager_rotate_banners is not defined

i am using the code in the header but i have also tried it on a single.php but get the same results

Any input would be much appreciated

https://www.ads-software.com/extend/plugins/useful-banner-manager/