MathML in DocBook 5 with Relax NG schema in Oxygen

Hello All,

I am trying to get MathML working with Oxygen for DocBook 5.0b6 with
Relax NG schema. I am new to Relax NG schema and Oxygen, and probably
doing something stupid. 

I am referencing the DocBook V5.0, The Transition Guide:
Procedure 1. Extending the DocBook schema with the MathML schema, using
the the XML syntax of RELAX NG—dbmathml.rng. I have also followed the Figure 2. Adding
a new schema association in oXygen

I am receiving the following validation error: 

SystemID: C:\xml\rng\dbmathml.rng

Description: java.io.FileNotFoundException-C:\xml\rng\relaxng.dtd (The
system cannot find the file specified)

It appears to be looking for an XML DTD rather than a Relax NG
schema. Below is the contents of dbmathml.rng.

Many thanks to anyone who can help me. 

Ellyn Larson

--------------------------------------------------------------

<?xml version="1.0" encoding="UTF-8"?>

<grammar xmlns="http://relaxng.org/ns/structure/1.0">

    

    <include href="C:/xml/DocBook/xml/rng/docbook.rng">

        <define name="db._any.mml">

            <externalRef href="C:/xml/rng/mathml/mathml2.rng"/>

        </define>

        

        <define name="db._any.svg">

            <externalRef href="svg/svg11.rng"/>

        </define>

        

        <define name="db._any">

            <element>

                <anyName>

                    <except>

                        <nsName
ns="http://docbook.org/ns/docbook"/>

                        <nsName
ns="http://www.w3.org/1999/xhtml"/>

                        <nsName
ns="http://www.w3.org/1998/Math/MathML"/>

                        <nsName ns="http://www.w3.org/2000/svg"/>

                    </except>

                </anyName>

                <zeroOrMore>

                    <choice>

                        <attribute>

                            <anyName/>

                        </attribute>

                        <text/>

                        <ref name="db._any"/>

                    </choice>

                </zeroOrMore>

            </element>

        </define>

    </include>

    

</grammar>

-- 

Ellyn Larson

Portalyx B.V.

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