fread() fails with large files

Hi. I am using Linux/Apache with PHP 4.1.2. I have been experiencing this problem since upgrading from an earlier version of PHP 4. My script forces a download of a PDF file after looking up some info in a database. The code looks like this: $file="/path/to/file"; $fp = fopen($file, "r"); $size=filesize($file); $contents = fread($fp, $size); fclose($fp); Header("Content-Type: $type"); Header("Content-Disposition: attachment; filename=$downloadname"); header("Content-Length: $size"); header("Content-Transfer-Encoding: binary"); echo $contents; filesize() is reporting the size properly. The code works perfectly for smaller files, but the fread() fails for files larger than 19 MB or so and I got a page cannot be displayed error. I know that it is fread() which is causing the problem because I commented out all the code that follows it and still get the error. All the files being downloaded are PDF files. Can anyone shed some light on this?