If you are still having this problem, check that your BI Publisher Desktop version matches (or at least is close) to your BI Publisher version.
I recently struggled with creating a PDF based on an RTF file and I just kept getting a blank pdf. The problem was that the server was running BI Publisher 10 and I was using BI Publisher Desktop 11 to create the rtf. Once I changed my Desktop version to 10 and recreated the rtf file, it worked like a charm.
RTF templates created with the BI Publisher 11g Word Plug-In will not work when using BI Publisher 10g on the server - unless the compatibility mode is used. To do this, start Word, navigate to the BI Publisher Plug-In menu, click options, click the "Build" tab, and then select "Backwards Compatible" for "Form Field Size.