In modules/Manufacturers/customer_manufacturers_list.php, change the navigation bit at the bottom to look like this:
PHP Code:
$smarty->assign("navigation_script","manufacturers.php?manufacturerid=".$manufacturerid."&sort=".$sort."&sort_direction=".$sort_direction . ($catid?'&catid='.$catid:''));
I found a client's manfacturer categories were not paginating properly, that change fixed the problem