send file to browser via php - problem with IE

hi,

im creating a file on the fly (can be text, tiff, jpg, pdf, pretty much everything).
now i want to send this file to the browser, instead of saving it somewhere on my server and just print out the link to this file - i dont wanna let the user know the file location.

my code looks like this:
(resources.php)

//generate file here
//save properties like name, size and real path in $my_file

if(isset($my_file)) {
	//$filetype = mime_content_type($my_file['path_real']);
    header('Content-Length: '. filesize($my_file['path_real']));
    if (in_array($extension, array('jpg', 'jpe', 'jpeg', 'gif', 'png')))
	{
		header("Content-disposition: inline; ".$my_file['name']);
		header('Content-transfer-encoding: binary');
	}
	else
	{
		// force files to be downloaded because of a possible XSS issue in IE
		header('Content-Disposition: attachment; filename='.$my_file['name']);
	}
	header('Content-type: application/octet-stream');
	readfile($my_file['path_real']);
}
else {
	header("HTTP/1.0 404 Not Found");
}

PHP:

this works fine in FF and in my IE, but on other peoples IE i get an error:
IE cannot download resources.php from mysite.com.
any idea how to do this...?