这段代码发送outlook邮件失败，哪儿错了呢？初学PHP，多多关照

<?php



$dtStart = '20090825T131415Z';//yyyymmddThhmmssZ

$dtEnd = '20090826T151617Z';

//--------------------

//create text file

$ourFileName = "icsFile/calendar.txt";

$ourFileHandle = fopen($ourFileName, 'w') or die("can't open file1");

fclose($ourFileHandle);

//

//edit temp file

$myFile = "icsFile/calendar.txt";

$fh = fopen($myFile, 'w') or die("can't open file2");



$stringData = "

BEGIN:VCALENDAR\n

PRODID:-//Microsoft Corporation//Outlook 11.0 MIMEDIR//EN\n

VERSION:2.0\n

METHOD:REQUEST\n

BEGIN:VEVENT\n

ORGANIZER:MAILTO:organizer@domain.com\n

DTSTAMP:".date('Ymd').'T'.date('His')."\n

DTSTART:$dtStart\n

DTEND:$dtEnd\n

TRANSP:OPAQUE\n

SEQUENCE:0\n

UID:".date('Ymd').'T'.date('His')."-".rand()."-domain.com\n

SUMMARY:do something someware\n

DESCRIPTION:  This is just a test\n

PRIORITY:5\n

X-MICROSOFT-CDO-IMPORTANCE:1\n

CLASS:PUBLIC\n

END:VEVENT\n

END:VCALENDAR";

fwrite($fh, $stringData);

fclose($fh);





//email temp file

    $fileatt = "icsFile/calendar.txt"; // Path to the file

    $fileatt_type = "application/octet-stream"; // File Type

    $fileatt_name = "ical.ics"; // Filename that will be used for the file as the attachment



    $email_from = "xxx@xxxx.com"; // Who the email is from

    $email_subject = "Email test"; // The Subject of the email

    $email_message = "this is a sample message \n\n next line \n\n next line"; // Message that the email has in it



    $email_to = "yyyy@yyyy.net"; // Who the email is too



    $headers = "From: ".$email_from;



    $file = fopen($fileatt,'rb');

    $data = fread($file,filesize($fileatt));

    fclose($file);



    $semi_rand = md5(time());

    $mime_boundary = "==Multipart_Boundary_x{$semi_rand}x";



    $headers .= "\nMIME-Version: 1.0\n" .

    "Content-Type: multipart/mixed;\n" .

    " boundary=\"{$mime_boundary}\"";



    $email_message .= "This is a multi-part message in MIME format.\n\n" .

    "--{$mime_boundary}\n" .

    "Content-Type:text/html; charset=\"iso-8859-1\"\n" .

    "Content-Transfer-Encoding: 7bit\n\n" .

    $email_message . "\n\n";



    $data = chunk_split(base64_encode($data));



    $email_message .= "--{$mime_boundary}\n" .

    "Content-Type: {$fileatt_type};\n" .

    " name=\"{$fileatt_name}\"\n" .

    //"Content-Disposition: attachment;\n" .

    //" filename=\"{$fileatt_name}\"\n" .

    "Content-Transfer-Encoding: base64\n\n" .

    $data . "\n\n" .

    "--{$mime_boundary}--\n";



    $ok = @mail($email_to, $email_subject, $email_message, $headers);

        if($ok) {



    } else {

    die("Sorry but the email could not be sent. Please go back and try again!");

    }



?>