Outputting a PDF.

I have a pdfs saved in a database (created with pdflib). When I output them in firefox, it works just great everytime. But when I try in IE, it doesn't always work. I know, I know, it sounds like a browser issue, but here's the problem. I figured out that when I run session_start(), the pdf never shows up in IE. When I don't run it, it works just as well as in firefox. When I put my header calls to set the content type to application/pdf before the session_start() call, IE spits out an error: "Internet Explorer cannot display the webpage Most likely causes: You are not connected to the Internet. The website is encountering problems. There might be a typing error in the address. " Anyone know of a fix for this?