I started getting this issue when using CFDOCUMENT one day. 

cfdocument java.io.IOException: Parsing problem occurred during the rendering process of this document.

I typically use Coldbox as a framework so in this case I had a layout where I was CFDOCUMENT to do all my PDF "rendering". So the customer reported to me that the server has an issue creating PDFs. I tried everything only to learn the basically CFDOCUMENT if very picky when it comes to W3C validation. In my CFDOCUMENT, I had done a CFINCLUDE on my CSS. That CSS was the cause of my IOException problem.

<style type="text/css" rel="stylesheet">

        <cfinclude template="/includes/css/style.css"  >

</style>

I modified my CSS and the problem went away. So hopefully this saves you some time.

Validate your HTML:  http://validator.w3.org/
Validate your CSS:  http://jigsaw.w3.org/css-validator/