ทำระบบเขียน แก้ไข บทความ พอทิ้งไว้เกิน15 นาที แล้ว submit มันดีดตัวlogout ออกเลย และบทความหาย ต้องไปแก้ใน phpmyadmin เกิดจากสาเหตุอะไรคะ

<?php
header("Content-type: text/html; charset=utf-8");
session_start();
ob_start();
if (empty($_SESSION ['username'])) {
    if(($_SESSION['member_class']!="admin") or ($_SESSION['member_class']!="staff")) {
        header('Location:index.php');
    }
}
$name = "admin_article_add.php" ;
$path_pic = "article" ;

include "startconnect.inc.php";
$article_title = $_POST["article_title"];
$article_type_id = $_POST["slcarticletype"];
if (isset ($_POST["slcarticlesubtype"]))
{
$article_subtype_id = $_POST["slcarticlesubtype"];
}
else
{
    $article_subtype_id = 0;
}
$article_predetail = $_POST["predetail"];

$pic_title = $_FILES['article_pic_title']['name'];
list($file_name,$ext_name) = split("\.",$pic_title) ;
$article_pic_title  =  time().".".$ext_name ;
$article_detail = ($_POST["FCKeditor1"]);

//$tpic = $_FILES['tpic']['name'];
//list($file_name,$ext_name) = split("\.",$tpic) ;
//$tpic  =  time().".".$ext_name ;

//$detail= addslashes($_POST["detail"]); 
$post_by = $_SESSION["memeber_id"] ;
$article_view = 0 ;
$article_vote = 0 ;
//$post_date = date("Y-m-d") ;
//$post_time = date("G:i:s") ;
$update_date = $_POST['update_date'];
$update_time = date("G:i:s") ;
$ip_address = $_SERVER['REMOTE_ADDR'] ;


if(($_FILES['article_pic_title']['type'] =="image/pjpeg")or($_FILES['article_pic_title']['type'] =="image/jpeg")or($_FILES['article_pic_title']['type'] =="image/gif")or($_FILES['article_pic_title']['type'] =="image/png")or($_FILES['article_pic_title']['type'] =="application/x-shockwave-flash")) {
if($_FILES['article_pic_title']['size']<=2000000) {
if(copy($_FILES['article_pic_title']['tmp_name'],"picture/" . $path_pic . "/" . $article_pic_title)) {
$detail_pic  = "Tempname = ".$_FILES['article_pic_title']['tmp_name']."<br>";
$detail_pic .= "Filename = ".$_FILES['article_pic_title']['name']."<br>";
$detail_pic .= "Filetype = ".$_FILES['article_pic_title']['type']."<br>";
$detail_pic .= "Filesize = ".$_FILES['article_pic_title']['size']."<br>";
$detail_pic .= "****************<br>";
$detail_pic .= "<font color = \"yellow\" size = \"4\">Upload Success</font>" ;
$_SESSION['result_upload'] = $detail_pic ;
$complete_upload = "yes" ;
}
else {
$err_upload = "ไม่สามารถ Upload รูปภาพได้ <br>" ;
$_SESSION['result_upload'] = $err_upload ;
$complete_upload = "no" ;
$complete_sql = "ไม่สามารถเพิ่มรูปภาพของ $article_title ได้ <br>" ;
$_SESSION['complete_upload'] = $complete_sql ;
header('Location:admin_article.php');
}
}
else {
$err_upload = "ขนาดรูปภาพต้องไม่เกิน 2M <br>" ;
$_SESSION['result_upload'] = $err_upload ;
$complete_upload = "no" ;
$complete_sql = "ไม่สามารถเพิ่มรูปภาพของ $article_title ได้ <br>" ;
$_SESSION['complete_upload'] = $complete_sql ;
header('Location:admin_article.php');
}
}
else {
$err_upload = "รูปภาพต้องเป็น .jpg , .png , .gif , .swf เท่านั้น <br>" ;
//$err_upload .="Filename = ".$_FILES['banner']['name']." Filetype = ".$_FILES['banner']['type']."ครับ<br>";
$_SESSION['result_upload'] = $err_upload ;
$complete_upload = "no" ;
$complete_sql = "ไม่สามารถเพิ่มรูปภาพของ $article_title ได้ <br>" ;
$_SESSION['complete_upload'] = $complete_sql ;
header('Location:admin_article.php');
}


$sql_add_article  = "insert into tblarticle (article_title,article_type_id,article_subtype_id,article_predetail,article_pic_title,article_detail,article_pic_detail,member_id,article_view,article_vote,update_date,update_time,ip_address) " ;
$sql_add_article .= "values ('$article_title','$article_type_id','$article_subtype_id','$article_predetail','$article_pic_title','$article_detail','$article_pic_detail','".$_SESSION["member_id"]."','$article_view','$article_vote','$update_date','$update_time','$ip_address')" ;
$_SESSION["sql"] = $sql_add_article ;
if ($complete_upload == "yes") {
    mysql_query($sql_add_article);
    header('Location:admin_article.php');
}
mysql_close($connect);
ob_end_flush();
?>