ilk seçenek seçmez ise hata veriyor bunun sebebi ne olabilir?

      <?php
      while ($row = mysql_fetch_array($receiverler)) {
      ?>
    <tr>
      <td class="table_body2" width="30%"><?=$row['receiver_markasi']?></td>
      <td class="table_body2" width="27%"><?=$row['receiver_tipi']?></td>
      <td class="table_body2" width="26%"><?=$row['receiver_ozelligi']?></td>
      <td class="table_body2" width="8%"><?=$row['receiver_fiyati']?><?=$row['receiver_para_cinsi']?></td>
      <td class="table_body2" width="9%">
      <input type="checkbox" name="receiver_id[]" value="<?=$row['id']?>">
      </td>
      <td class="table_body2" width="9%">
        <select size="1" name="receiver_amount[]">
        <option></option>
        <?php
        $sayi = 1;
        while($sayi < $encok=$dairesayisi['secilen_daire_sayisi']+1) {
        echo '<option value="'.$sayi.'">'.$sayi.'</option>';
        $sayi++;
        }
       ?>
      </select>
      </td>
    </tr>
    <?php
     }
     ?>

          $id = $_SESSION['lastid'];
          for($i=0; $i<count($_POST['receiver_id']); $i++) {
          $receiver_id[] = $_POST['receiver_id'][$i];
          $receiver_amount[] = $_POST['receiver_amount'][$i];
          }
          $values = array();
          for($i=0; $i<count($receiver_id); $i++) {
          $values[]="({$id}, {$receiver_id[$i]}, {$receiver_amount[$i]})";
          }         

          $receiver_amounts=mysql_query("INSERT INTO receiver_amounts (`id`, `receiver_id`, `receiver_amount`) VALUES " . implode(", ", $values));
          if (!$receiver_amounts)
         {
         die(mysql_error());
         }