using plugins

I have a page that needs to load some large PDF files. I want to be able to let the user know that it is downloading by showing a loading... and percent complete as it goes along. I tried using the below script to see if I could get it to work. The page download the file, but then displays the file as text. How do I get the browser to load the adobe acrobat reader plugin and view the variable information with it? Or should I be doing thin in an other manner? Any sugestions are greatly appreciated. <?php $filename="microliteXPflyer.pdf"; $fp=fopen($filename,"rb"); if ($fp) { header('<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">'); header("Content-type: application/octet-stream\n" ); header("Content-transfer-encoding: binary\n"); header("Content-length: " . filesize($filename) . "\n"); header("Content-disposition: attachment; filename=$filename\n"); $contents=""; while (!feof($fp)) {

    $contents .= fread($fp, 10000);

} fclose($fp); print($contents); } // end if ?>