4.0.2 not able to send files?

Greetings, Is there a known problem with PHP 4.0.2 and sending files to clients? I generate PDF files with cpdf, then make <A> tags that point to the files. When I upgraded from 4.0.1.pl2 to 4.0.2 the ability to "pull up" one of the PDFs appears to have broken... well, not completely, but 5 out of 10 times will fail consistently. If I go directly to the file on the server and download it to my machine via FTP or SAMBA then I can open the file without problem, so it does not _seem_ to be the PDF files. Any insight on this would be greatly appreciated. Thanks, Matthew