PhpMailer: Language string failed to load: execute/usr/sbin/sendmail

Hi, i am trying to use phpmailer, but i have some error...

Error is: Language string failed to load: execute/usr/sbin/sendmail;

code is:

<?php
include_once('php/get_category.php');
include_once('php/get_slike.php');
if ($_GET['status']=="sent") {
 $status="sent";
}
if (isset($_POST['SenderName']) && isset($_POST['SenderEmail'])
 && preg_match("/^[a-z0-9&\'\.\-_\+]+@[a-z0-9\-]+\.([a-z0-9\-]+\.)*+[a-z]{2}/is", $_POST['SenderEmail'])) {
require_once("phpmailer/class.phpmailer.php");
$SenderName = $_POST['SenderName']; 
$SenderEmail = $_POST['SenderEmail']; 
$SenderMessage = $_POST['SenderMessage'];

 // Pokretanje i obrada PHPmailer skripte
 $mail = new PHPMailer(); // using php "mail()"
 $mail->IsSendmail(); // SendMail transport
 $mail->Subject = "Poruka sa ZID2 sajta"; 
 $mail->FromName = $SenderName; 
 $mail->From = $SenderEmail; 
 $mail->Body = $SenderMessage;
 $mail->WordWrap = 50;
 $mail->IsHTML(true);
 $mail->CharSet="utf-8";
 $mail->AddAddress("srdjan.nezic@yahoo.com"); 
 // $mail->AddBCC("nenad@krojac.com"); 

 // Obrada slanja i provera
 if($status != "sent") {
 if($mail->Send()) {
 header("Location: ?status=sent");
 } else {
 $status = "Error";
 $poruka_greska="Mailer Error: " . $mail->ErrorInfo; 
 echo '<script type="text/javascript">alert('.'"'.$poruka_greska.'"'.');</script>';
 }
 }
}
?> 

site where i try to use this script is http://zid2proba.comlu.com/contact.php

so, what's wrong here?