แปลกครับ ผมงงกับการวนลูป ปกติมันจะทำงาน ตามเงื่อนไข

<?

header("Content-type: application/vnd.ms-excel");
header("Content-Disposition: attachment; filename=$file.xls");


 function alphanumeric_rand($num_require=8) {
$alphanumeric = array('A','B','C','D','E','F','G','H','I','J','K','L','M','N','P','Q','R','S','T','U','V','W','X','Y','Z',0,1,2,3,4,5,6,7,8,9);
if($num_require > sizeof($alphanumeric)){
echo "Error alphanumeric_rand(\$num_require) : \$num_require must less than " . sizeof($alphanumeric) . ", $num_require given";
return;
}
$rand_key = array_rand($alphanumeric , $num_require);
for($i=0;$i<sizeof($rand_key);$i++) $randomstring .= $alphanumeric[$rand_key[$i]];
return $randomstring;
}

?>

 <?   $x = 1;
            while ($x <= $SN_gQty) {
                
				  ?>
                <table width="100%" border="1" cellspacing="0" cellpadding="0">
  <tr>
   <td width="50">&nbsp;</td>
    <td height="25"><?=$SN_Lot.alphanumeric_rand(14)?></td>
    <td width="50">&nbsp;</td>
   <td width="50">&nbsp;</td>
    <td width="50">&nbsp;</td>
   <td width="50">&nbsp;</td>
    <td width="50">&nbsp;</td>
     <td width="50">&nbsp;</td>
      <td width="50">&nbsp;</td>
       <td width="50">&nbsp;</td>
        <td width="50">&nbsp;</td>
         <td width="50">&nbsp;</td>
          <td width="50">&nbsp;</td>
           <td width="50">&nbsp;</td>
            <td width="50">&nbsp;</td>
             <td width="50">&nbsp;</td>
              <td width="50">&nbsp;</td>
               <td width="50">&nbsp;</td>
                <td width="50">&nbsp;</td>
                 <td width="50">&nbsp;</td>
                  <td width="50">&nbsp;</td>
  </tr>
</table>  
                  <?
				  
                  $x++;
            }
			?>