ปัญหาเรื่องการใช้ header("Content-type: application/vnd.ms-word"); ครับ

<? 
header("Content-type: application/vnd.ms-word");
header ('Content-type: text/html; charset=windows-874');
header("Content-Disposition: attachment; filename=report_".$_GET[date_search].".doc");

 include('system/system.engine.php');
 
if($_GET[date_search] != "") {
  $dbo->query_string = "SELECT * FROM log_file_bank WHERE time_stamp like '".$_GET[date_search]." %' ORDER BY lb_id ASC " ;
} else { 
    $dbo->query_string = "SELECT * FROM log_file_bank ORDER BY lb_id ASC " ;
	}
   $dbo->query() ;
   if($dbo->num_rows() > 0) {
?>
<table width="100%" border="0" cellspacing="1" cellpadding="1">
 <tr>
    <td colspan="6" align="center">&nbsp;</td>
  </tr>
  <tr>
    <td width="10%" align="center" bgcolor="#2B80FF"><strong><font color="#FFFFFF" size="2">รหัสพนักงาน</font></strong></td>
    <td width="15%" align="center" bgcolor="#2B80FF"><strong><font color="#FFFFFF" size="2">Username</font></strong></td>
    <td width="30%" align="center" bgcolor="#2B80FF"><strong><font color="#FFFFFF" size="2">Session ID</font></strong> </td>
    <td width="20%" align="center" bgcolor="#2B80FF"><strong><font color="#FFFFFF" size="2">TimeStamp</font></strong> </td>
    <td width="15%" align="center" bgcolor="#2B80FF"><strong><font color="#FFFFFF" size="2">รหัสสมาชิก</font></strong> </td>
    <td width="30%" align="center" bgcolor="#2B80FF"><strong><font color="#FFFFFF" size="2">ชื่อสมาชิก</font></strong> </td>
  </tr>
  <?php
   while($rs = $dbo->fetch_array()){ 
   ?>
  <tr>
    <td align="center" class="data_list" ><?=$rs['memberEmpID'];?></td>
    <td align="left" class="data_list">&nbsp;&nbsp;<?=$rs['memberusername'];?></td>
    <td align="center" class="data_list"><?=$rs['sessionid'];?></td>
    <td align="center" class="data_list"><?=$rs['time_stamp'];?></td>
    <td align="center" class="data_list"><?=$rs['membership_no'];?></td>
    <td align="center" class="data_list"><?=$rs['member_name'];?></td>
  <?
   }
  ?>
  <tr>
    <td colspan="6">&nbsp;</td>
  </tr>
</table>
<?
}
?>