Zasílání emailu přes server

if (isset($_POST["potvrd"])){
        
          $result = mysql_query("SELECT * FROM zakaznici WHERE login_name='$login'");
          $z=mysql_fetch_array ($result);

      if($html=="mail"){
            $headers = 'From: krelinapetr.p4a.skola@vos-kh.cz';
            $headers .='Reply-To: krelinapetr.p4a.skola@vos-kh.cz';
            $headers .= 'Content-Type: text/html; charset="iso-8859-1"';
            $headers .='X-Mailer: PHP/' . phpversion();
          }else{
            $headers = 'From: krelinapetr.p4a.skola@vos-kh.cz';
            $headers .='Reply-To: krelinapetr.p4a.skola@vos-kh.cz';
            $headers .= 'Content-Type: text/plain; charset="iso-8859-1"';
            $headers .='X-Mailer: PHP/' . phpversion();
          }
          
          
            $to      = $z["mail"];
            $subject = 'Objednávka';
            $message = '<table>';
            $message .= '<tr><td>Název</td>';
            $message .= '<td>Cena za kus bez DPH</td>';
            $message .= '<td>Počet kusů</td>';
            $message .= '<td>Cena za všechny kusy bez DPH</td>';
            $message .= '<td>DPH</td>';
            $message .= '<td>Cena za kus s DPH</td>';
            $message .= '<td>Cena za všechny kusy s DPH</td></tr>';
            
            for ($i=1;$i<=$pocet;$i++){ 
              $z=mysql_fetch_array ($result);
              if ($login == $z['login']){        
         
          $cenaBDPH=$z["cena"];
          $ccBDPH=$cenaBDPH * $z["pocet"];
          $cenasDPH=$cenaBDPH * (1+$z["dph"]/100);
          $cs=round($cenasDPH);
          $ccsDPH=$cs * $z["pocet"];
            
            
            $message .= "<tr>";
            $message .= "<td>" . $z["nazev"] . "</td>";
            $message .= "<td>" . $cenaBDPH . ",- Kč</td>";
            $message .= "<td>" . $z["pocet"]. "</td>";
            $message .= "<td>" . $ccBDPH . ",- Kč</td>";
            $message .= "<td>" . $z["dph"] . "%</td>";
            $message .= "<td>" . $cs . ",- Kč</td>";
            $message .= "<td>" . $ccsDPH . ",- Kč</td>";    
            $message .= "</tr></table>";
            
          
        $vsebDPH=$vsebDPH + $ccBDPH;
        $vsesDPH=$vsesDPH + $ccsDPH;
        
        }} 
        
        $message .= "<p>Celková cena bez DPH: <strong>" . $vsebDPH . ",-Kč</strong></p>";
        $message .= "<p >Celková cena s DPH: <strong>" . $vsesDPH . ",-Kč</strong></p>";
          
          mail($to, $subject, $message, $headers);
          
       
}

 if($html=="mail")