Linux droit d'execution sur un prog via php

          <!DOCTYPE html><html xmlns="http://www.w3.org/1999/xhtml"> 
  <head> 
    <meta http-equiv="Content-Type" content="text/html;charset=UTF-8" /> 
    <title>Application</title> 
  </head> 
  <body> 
    <p><br /> 
    </p> 
    <p></p> 
    <table border="1" style="width: 100%"> 
      <tbody> 
        <tr><td>Amule<br /> 
          </td> 
          <td><form method="post" 
 action="" name="Application1-On"><input name="Application1-On" value="Démarrer" type="submit"><br /> 
          </td> 
          <td><form method="post" 
 action="" name="Application1-Off"><input name="Application1-Off" value="Arrêter" type="submit"><br /> 
          </td> 
          <td><form method="post" 
 action="" name="Application1-Off"><input name="Application1-re" value="Redémarrer" type="submit"><br /> 
          </td> 
        </tr> 
      </tbody> 
    </table> 
<?php 

if (isset($_POST['Application1-On'])){ 

$commande = "/etc/init.d/amule-daemon start"; 
exec("$commande", $top, $error ); 
echo nl2br(implode("\n",$top)); 
if ($error){ 
    exec('/usr/bin/top n 1 b 2>&1', $error ); 
    echo "Error: "; 
    exit($error[0]); 
} 
} 
?>  
    <p><br /> 
    </p> 
  </body> 
</html>

root@debian:# cat /var/log/apache2/error.log 
sh: /etc/init.d/service: not found 
start-stop-daemon: unable to set gid to 1000 (Operation not permitted)