below is an error generated by a script that functions fine on another server. it refers to a class used for sending email via a tell a friend form.

Fatal error: Uncaught exception 'Exception' with message 'Sending mail failed.' in /home/xxx/public_html/scripts/class.simpleMail.php:80 Stack trace: #0 /home/xxx/public_html/products/taf.php(30): simpleMail->send() #1 {main} thrown in /home/xxx/public_html/scripts/class.simpleMail.php on line 80
line 80 below, where the error's coming from.

if (!mail($this->to,$this->subject,$this->message,$this->headers)){
throw new Exception('Sending mail failed.');
return FALSE;}
since it works fine on another server im thinking this is something to do with the php config? what does stack trace mean?