Here’s a temporary solution which I have been using, but remember, you will have to make this change after every update of this Plugin. Hope it helps.
To change the default Page Break on Download Manager from 10 to (say) 15
Editing download-manager/download-manager.php (active)
In Plugins – Installed Plugins,
Click on ‘Download Manager – Edit
Scroll down to this function.
function wpdm_embed_category($id){
global $wpdb, $current_user, $post, $wp_query;
$postlink = get_permalink($post->ID);
get_currentuserinfo();
$user = new WP_User(null);
$categories = maybe_unserialize(get_option(“_fm_categories”,true));
$category = $categories[$id];
$total = $wpdb->get_var(“select count(*) from ahm_files where category like ‘%\”$id\”%'”);
$item_per_page = 15; Default was 10 items($total);
$pag->limit($item_per_page);
$pag->currentPage($page);