Hello HSH,
add this:
if(!defined('WPDM_ADMIN_CAP'))
define('WPDM_ADMIN_CAP','edit_posts');
if(!defined('WPDM_MENU_ACCESS_CAP'))
define('WPDM_MENU_ACCESS_CAP','edit_posts');
to just under this line:
/**
* Define cookie domain if it is already not defined
*/
in the ../plugins/download-manager/download-manager.php
file and save.
it will always solve the issue.
Thanks