php upload file มีปัญหาเกี่ยวกับการอัพโหลดไฟล์คับ รายละเอียดด้านในคับ

<?
	$objConnect = mysql_connect("localhost","root","root") or die("Error Connect to Database");
	mysql_query("set names UTF8");
	$objDB = mysql_select_db("lenning");
	$strSQL = "SELECT * FROM lesson";
	$objQuery = mysql_query($strSQL) or die ("Error Query [".$strSQL."]");
?>

<?
	$objConnect = mysql_connect("localhost","root","root") or die("Error Connect to Database");
	$objDB = mysql_select_db("lenning");
	$strSQL = "SELECT * FROM lesson where Lesson_Id ='$Lesson_Id'";
	mysql_query("set NAMES utf8");
	$objQuery = mysql_query($strSQL) or die ("Error Query [".$strSQL."]");
	mysql_query("set NAMES utf8");
	$row = mysql_fetch_array($objQuery);
?>

<input type="text" name="Keyword"id="Keyword"value="<?=$row['Keyword']?>" />
<input type="hidden" name="Lesson_Detailed" value="<?=$row['Lesson_Detail']?>"  />

<input type="hidden" name="Date" value="<?=$row['Date']?>"  />

<input type="hidden" name="Lesson_Id" value="<?=$row['Lesson_Id']?>"  />

<?
	if(move_uploaded_file($_FILES["Lesson_Detail"]["tmp_name"],"files/".$_FILES["Lesson_Detail"]["name"]))
	{
		echo "อัพเดทข้อมูลสำเร็จ<br>";

		//*** Insert Record ***//
		$objConnect = mysql_connect("localhost","root","root") or die("Error Connect to Database");
		$objDB = mysql_select_db("lenning");
		$strSQL = "INSERT INTO lesson ";
		$strSQL .="(Lesson_Name,Lesson_Detail,Date,Keyword) VALUES ('".$_FILES["Lesson_Detail"]["name"]."','".$_POST["Lesson_Name"]."',".$_POST["Date"]."',".$_POST["Keyword"]."')";
		$objQuery = mysql_query($strSQL);		
	}
?>