add subscriber bug

fix:
set default value in line 88 to:
function campaignmonitor_add_subscriber($api_key, $list_id, $name, $email, $show_errors=true) {

php error:
Missing argument 5 for campaignmonitor_add_subscriber(), called in /var/www/vhosts/consciousdancer.com/httpdocs/modules/campaignmonitor/campaignmonitor.module on line 496 and defined in /var/www/vhosts/consciousdancer.com/httpdocs/modules/campaignmonitor/campaignmonitor.module on line 88.