ช่วยทีครับ ผมทำList ข้อมูลแบบPaging(แบ่งหน้า) มันโชว์แค่หน้าแรกอะครับ พอกดหน้า2มันErrorอะครับ

<?
include "databaseconnect2.php";

echo "<div align = 'right'><a href ='logout.php'>Logout <a></div>";
echo"<br><br>";
echo "<div align='center'>Dotarai Create Invocie</div>";
echo"<form action='createinvoice2.php' method='post' >";
echo"<table align='center'>";
echo"<tr><td>BP Name: </td>";
echo "<td><select name = 'bp'>";
echo"<option value=''>BP Name </option>";


$sql= "select webreg__user.username,webreg__user.fname,webreg__user.lname,webreg__user.org from
       bpuser,webreg__user where bpuser.webreg__userId= webreg__user.id
      order by webreg__user.org";
$result= mysql_query($sql) or die (mysql_error()); 
while($rows = mysql_fetch_array($result))
{
   
   echo"<option value=".$rows['username'].">".$rows['org']."(".$rows['fname']." "
   .$rows['lname'].")</option>";
  
}
echo "</select></td></tr>";

echo"<br>";
echo"<tr><td>Date/Month/Year: </td>";

echo"<td><select name = 'date'>";
echo"<option value=''>All</option>";
for($i=1;$i<=31;$i++)
{
   if($i<10)
   {
    $j= '0'.$i;
 echo"<option value='$j'>$j</option>";
   }
   else
   {
      echo"<option value='$i'>$i</option>";
   }
}
echo"</select>";





echo "<select name = 'month'>";
echo"<option value=''>Month</option>";
echo"<option value='01'>January</option>";
echo"<option value='02'>February</option>";
echo"<option value='03'>March</option>";
echo"<option value='04'>April</option>";
echo"<option value='05'>May</option>";
echo"<option value='06'>June</option>";
echo"<option value='07'>July</option>";
echo"<option value='08'>August</option>";
echo"<option value='09'>September</option>";
echo"<option value='10'>October</option>";
echo"<option value='11'>November</option>";
echo"<option value='12'>December</option>";
echo"</select>";



echo "<select name = 'year'>";
echo"<option value=''>Year </option>";
for($i=2007;$i<=date('Y');$i++)
{
echo"<option value='$i'>$i</option>";
}
echo"</td></tr></select>";
echo"<br>";
echo"<tr><td>Record Per Page: </td>";
echo "<td><select name = 'record'>";
echo"<option value=''>Record</option>";
for($i=1;$i<=10;$i++)
{
echo"<option value='$i'>$i</option>";
}
echo"</td></tr></select>";
echo"<br>";

echo"<tr><td colspan='2'><div align='center'><input type='submit' value='Submit'></div>";
echo"</td></tr></table>";
echo "</form>";

mysql_close($conn2);
?>

<?
include "databaseconnect2.php";
// Varible Detail
$bp = $_POST["bp"];  
$month = $_POST["month"];
$year = $_POST["year"];
$record = $_POST["record"];
$date = $_POST["date"];
$ym = $year."-".$month ;
$ymd = $year."-".$month."-".$date;


// Header Document

echo "<table align='center'>";
echo "<tr><th>DotArai Co.,Ltd.</th></tr>";
echo "<tr><td>131 Mu 9, Room INC1-216 Phahon Yothin Rd.,</td></tr>";
echo "<tr><td> Khlong Nueng, Khlong Luang, Pathum Thani 12120 </td></tr>";
echo "<tr><td>Tel : 0-2564-8038  Fax : 0-2564-8039 </td></tr>";
echo "<tr><td colspan='2'>Emai : [email protected]</td><td>เลขประจำตัวผู้เสียภาษี  :</td><td>3032001731</td></tr>";
echo "<tr><td>Invoice</td></tr>";
echo"</table>";


$sql= "select org,street1,city,sp,pc,voice,fax from webreg__user where username='$bp'";
$result= mysql_query($sql);
echo "<table align='center'>";
while($rows = mysql_fetch_array($result))
{
$da = date("d-M-Y");
$da2 = date("d")+7;
$da3 = date("M-Y");
echo "<tr><td col span='2'>Attn :</td><td>".$rows['org']." </td><td>Date :</td><td>".$da."</td></tr>";
echo "<tr><td></td><td> ".$rows['street1']." </td><td>Due Date :</td><td>".$da2."-".$da3."</td></tr>";
echo "<tr><td></td><td> ".$rows['city']." ".$rows['sp']." ".$rows['pc']."</td>
 <td>Invoice No. :</td><td></td></tr>";
 
 if($rows['voice']!="")
 echo "<tr><td>Tel :</td><td>0".substr($rows['voice'],3)." </td><td></td><td></td></tr>";
 
 else if($rows['voice']=="")
 echo "<tr><td>Tel :</td><td> </td><td></td><td></td></tr>";
 
 if($rows['fax']!="")
 echo "<tr><td>Fax :</td><td>0".substr($rows['fax'],3)." </td><td></td><td></td></tr>";
 
 else if($rows['fax']=="")
 echo "<tr><td>Fax :</td><td> </td><td></td><td></td></tr>";
 
}
echo"</table>";
echo"<table align = 'center'>";
echo "<th>Item</th><th>Description</th><th>Qty</th><th>Unit Price</th><th>Baht Amount</th>";




if($_POST["date"]=='')
{
    $x = $ym;
}
else if($_POST["date"]!='')
{
    $x = $ymd;
}


// Paging Detail
$sql= " select webreg__pending_order.domainname,webreg__pending_order.period,webreg__tax_invoice_item.description
       ,webreg__tax_invoice_item.unit_amount
       from webreg__pending_order,webreg__tax_invoice_item
       where  webreg__pending_order.invoice_item_id = webreg__tax_invoice_item.id
       and webreg__pending_order.username='$bp' and webreg__pending_order.process_date like'$x%'
       and webreg__pending_order.status='Approve' 
       
       UNION ALL
       
       select webreg__pending_renew.domainname,webreg__pending_renew.period,webreg__tax_invoice_item.description
       ,webreg__tax_invoice_item.unit_amount
       from webreg__pending_renew,webreg__tax_invoice_item
       where webreg__pending_renew.invoice_item_id = webreg__tax_invoice_item.id
       and webreg__pending_renew.username='$bp' and webreg__pending_renew.process_date like'$x%'
       and webreg__pending_renew.status='Approve'
       
       UNION ALL
       
       select webreg__pending_transfer_in.domainname,webreg__pending_transfer_in.period,
       webreg__tax_invoice_item.description,webreg__tax_invoice_item.unit_amount
       from webreg__pending_transfer_in,webreg__tax_invoice_item
       where webreg__pending_transfer_in.invoice_item_id = webreg__tax_invoice_item.id
       and webreg__pending_transfer_in.username='$bp' and webreg__pending_transfer_in.process_date like'$x%'
       and webreg__pending_transfer_in.status='Approve'";
      
      $result= mysql_query($sql);
      $Num_Rows = mysql_num_rows($result); 
      $Per_Page = $record;   // Record Per Page 
      $Page = $_GET["Page"]; 
if(!$_GET["Page"]) 
{ 
     $Page=1; 
} 
  $Prev_Page = $Page-1;
  $Next_Page = $Page+1; 
  $Page_Start = (($Per_Page*$Page)-$Per_Page);
  if($Num_Rows<=$Per_Page) 
{ 
     $Num_Pages =1; 
} 
else  if(($Num_Rows % $Per_Page)==0) 
{ 
     $Num_Pages =($Num_Rows/$Per_Page) ; 
} 
 else 
{ 
     $Num_Pages =($Num_Rows/$Per_Page)+1; 
     $Num_Pages = (int)$Num_Pages; 
} 
  

      
// Invoice Detail
$sql= " (select webreg__pending_order.domainname,webreg__pending_order.period,webreg__tax_invoice_item.description
       ,webreg__tax_invoice_item.unit_amount
       from webreg__pending_order,webreg__tax_invoice_item
       where  webreg__pending_order.invoice_item_id = webreg__tax_invoice_item.id
       and webreg__pending_order.username='$bp' and webreg__pending_order.process_date like'$x%'
       and webreg__pending_order.status='Approve' order by webreg__pending_order.process_date )
       
       UNION ALL
       
       ( select webreg__pending_renew.domainname,webreg__pending_renew.period,webreg__tax_invoice_item.description
       ,webreg__tax_invoice_item.unit_amount
       from webreg__pending_renew,webreg__tax_invoice_item
       where webreg__pending_renew.invoice_item_id = webreg__tax_invoice_item.id
       and webreg__pending_renew.username='$bp' and webreg__pending_renew.process_date like'$x%'
       and webreg__pending_renew.status='Approve' order by webreg__pending_renew.process_date  )
       
       UNION ALL
       
      ( select webreg__pending_transfer_in.domainname,webreg__pending_transfer_in.period,
       webreg__tax_invoice_item.description,webreg__tax_invoice_item.unit_amount
       from webreg__pending_transfer_in,webreg__tax_invoice_item
       where webreg__pending_transfer_in.invoice_item_id = webreg__tax_invoice_item.id
       and webreg__pending_transfer_in.username='$bp' and webreg__pending_transfer_in.process_date like'$x%'
       and webreg__pending_transfer_in.status='Approve' order by webreg__pending_transfer_in.process_date)
        LIMIT $Page_Start,$Per_Page";

$result= mysql_query($sql); 

while($rows=mysql_fetch_array($result))
{
 
  echo"<tr><td> </td><td>" .$rows['domainname']." (".$rows['description'].")</td>
  <td>".$rows['period']."</td><td>".$rows['unit_amount']/$rows['period']." </td><td>".$rows['unit_amount']."
  </td></tr>";
}
echo"</table>";

echo"<br>";
//Paging Detail
echo "Total  ".$Num_Rows."Record :".$Num_Pages." Page : ";

if($Prev_Page) 
{ 
     echo  " <a href='$_SERVER[SCRIPT_NAME]?Page=$Prev_Page'><<  
     Back</a> "; 
} 
  
for($i=1; $i<=$Num_Pages; $i++)
{ 
     if($i  != $Page) 
     { 
          echo  "[ <a href='$_SERVER[SCRIPT_NAME]?Page=$i'>$i</a> ]"; 
     } 
     else 
     { 
          echo  "<b> $i </b>"; 
     } 
} 
if($Page!=$Num_Pages) 
{ 
     echo  " <a href ='$_SERVER[SCRIPT_NAME]? 
     Page=$Next_Page'>Next>></a> "; 
} 
mysql_close($conn2);
?>