BI Publisher - Namespace prefix 'ref' used but not declared Error

I am writing a PX to use BI Publisher APIs to create a PDF document from a Word Template. The code is below.

FOProcessor processor = new FOProcessor();

processor.setData(data);

processor.setTemplate(getXSLTemplate(template, TEMP_OBJ_FILENAME));

processor.setOutputFormat(FOProcessor.FORMAT_PDF);

processor.setOutput(out);

processor.generate();

When I hit the last statement "processor.generate", I receive the error below. Any idea how I need to fix this?

org.xml.sax.SAXException: Namespace prefix 'ref' used but not declared.

oracle.xml.parser.v2.XPathException: Namespace prefix 'ref' used but not declared.

at oracle.xml.parser.v2.XSLBuilder.startElement(XSLBuilder.java:419)