The PHP form generates & ldquo; Object not found & rdquo; But still submits form data

I've got a simple php form for client info that when submitted, generates an object not found 404 error. The information I submitted is still being sent to the db successfully so I'm not sure why I'm seeing this error. Thanks in advance for the help.

<?php
$link=mysql_connect("localhost","root","");
  $database='clientinformation';
  if (!$link)
  die('Failed to connect to Server'.mysql_error());
  $db=mysql_select_db($database, $link);
  session_start();
  if(!$db)
  die('Failed to select Data Base '.mysql_error());

if(isset($_GET['process']))
   {
    $query = "Insert INTO `client_reg` (ClientName, Address, CNICNumber, MobileNumber, TelephoneNumber, CompanyName, ClientStatus, RegisterDate) values('$_POST[ClientName]', '$_POST[Address]','$_POST[CNICno]','$_POST[Mobileno]', '$_POST[Telephoneno]', '$_POST[Companyname]', '$_POST[Clientstatus]', '$_POST[RegisteredDate]')";
    //echo $query; exit;
    $result = mysql_query($query) or die(mysql_error());
    if(!$result)
    {
     $msg = "not Inserted";

    }
    else
    {
     $msg = "Inserted";
     header("location:ClientList.php?m=".$msg);
    }
   }
?>


Does Clientlist.php exist on your server? Remember that UNIX servers are case sensitive. If it's clientlist.php on the drive, you'll get a 404