header() problem in IE - php

Question

I have a function for outputting documents, images etc:
public function direct($theMimeType, $thePath)
{
header('Content-type: '.$theMimeType);
ob_clean(); // clean output buffer
flush(); // flush output buffer
readfile($thePath);
exit;
}
It works great in Firefox. The file opens whether it is PDF, DOCX or any other file. However, in IE it freezes and nothing shows up.
What could cause this?
EDIT:
I have added few other headers:
public function direct($theMimeType, $thePath)
{
$aSize = filesize($thePath);
$aBegin = 0;
$aEnd = $aSize;
$aFilename = end(explode('/', $thePath));
$aTime = date('r', filemtime($thePath));
$aContentDisposition = ('application/pdf' === $theMimeType) ? 'inline' : 'atachment';
header('HTTP/1.0 200 OK');
header("Content-Type: $theMimeType");
header('Cache-Control: public, must-revalidate, max-age=0');
header('Pragma: no-cache');
header('Accept-Ranges: bytes');
header('Content-Length:'.($aEnd-$aBegin));
header("Content-Range: bytes $aBegin-$aEnd/$aSize");
header("Content-Disposition: $aContentDisposition; filename=$aFilename");
header("Content-Transfer-Encoding: binary\n");
header("Last-Modified: $aTime");
header('Connection: close');
ob_clean(); // clean output buffer
flush(); // flush output buffer
readfile($thePath);
exit;
}
Well, it works in IE now but still it opens the file much slower than Firefox. There seems to be few seconds freeze up before the IE browser opens the file.

Answer 1

Make this file download directly, not using any scripts
make sure it works in IE
in firefox, use LiveHTTPHeaders to watch what headers being sent by web-server
in firefox, use LiveHTTPHeaders to watch what headers being sent by your script
make your script's headers the same as web-server's

Answer 2

Most of those headers aren't really necessary. I prefer to keep things simple:
header ('Expires: Mon, 26 Jul 1997 05:00:00 GMT'); // Date in the past
header ('Last-Modified: '.gmdate('D, d M Y H:i:s').' GMT'); // always modified
header ('Cache-Control: cache, must-revalidate'); // HTTP/1.1
header ('Pragma: public');
header ('Content-Type: '.$theMimeType);
header ('Content-Disposition: '.$aContentDisposition.'; filename="'.$aFilename.'"');
header ('Content-Transfer-Encoding: binary');
header ('Content-Length: '.$aSize);
Watch out for the \n at the end of your Content-Transfer-Encoding header.
The 'Pragma: public' is a workround specifically to handle a problem with IE and https connections. The other key difference is $aFilename in quotes.