79라인

<td class="td_name">
<label for="ad_subject" class="sound_only">배송지명</label>
<input type="text" name="ad_subject[<?php echo $i; ?>]" id="ad_subject" class="frm_input" size="12" maxlength="20" value="<?php echo $row['ad_subject']; ?>">
</td>

을

<td class="td_name">
<label for="ad_subject_<?php echo $i; ?>" class="sound_only">배송지명</label>
<input type="text" name="ad_subject[<?php echo $i; ?>]" id="ad_subject_<?php echo $i; ?>" class="frm_input" size="12" maxlength="20" value="<?php echo $row['ad_subject']; ?>">
</td>

으로 수정해야 할 것 같습니다.

mobile/shop/orderaddress.php 도 동일 ^^