PHP Sending Email Attachment Files ไฟล์ไม่เข้า Email ครับ

<?
$strTo = $_POST["txtTo"];
$strSubject = $_POST["txtSubject"];
$strMessage = nl2br($_POST["txtDescription"]);

//*** Uniqid Session ***//
$strSid = md5(uniqid(time()));

$strHeader = "";
$strHeader .= "From: ".$_POST["txtFormName"]."<".$_POST["txtFormEmail"].">\nReply-To: ".$_POST["txtFormEmail"]."";

$strHeader .= "\n";
$strHeader .= "Content-Type: multipart/mixed; boundary=\"".$strSid."\"\n\n";
$strHeader .= "This is a multi-part message in MIME format.\n";

$strHeader .= "--".$strSid."\n";
$strHeader .= "Content-type: text/html; charset=windows-UTF-8\n"; // or UTF-8 //
$strHeader .= "Content-Transfer-Encoding: 7bit\n\n";
$strHeader .= $strMessage."\n\n";

//*** Attachment ***//
if($_FILES["fileAttach"]["name"] != "")
{
$strFilesName = $_FILES["fileAttach"]["name"];
$strContent = chunk_split(base64_encode(file_get_contents($_FILES["fileAttach"]["tmp_name"])));
$strHeader .= "--".$strSid."\n";
$strHeader .= "Content-Type: application/octet-stream; name=\"".$strFilesName."\"\n";
$strHeader .= "Content-Transfer-Encoding: base64\n";
$strHeader .= "Content-Disposition: attachment; filename=\"".$strFilesName."\"\n\n";
$strHeader .= $strContent."\n\n";
}


$flgSend = @mail($strTo,$strSubject,null,$strHeader); // @ = No Show Error //
if($flgSend)
{
echo "<center>�觢��������º��������</center>";
}
else
{
echo " ��سҡ�͡��������´����ú��ǹ !!!! �к��������ö�觢��������";
}


?>