If you're trying to write a cgi script that will output PDF, make sure to set the proper MIME type - else the client/browser will probably try to interpret it as HTML.

BTW - putting PDF (or any large binary) files in a database sounds like a really bad idea, IMO. I'd suggest storing the files somewhere on the server, outside of the web root dir. Only store the path to each file in the DB. Then when your cgi script needs a file, rather than pull the file out of the DB, pull the path out of the DB, then read it from that path and write it to the browser.