Hi, I'm trying to register one schema and another included schemas, but I faced the trouble. If anyone knows something, would you tell me?

The structure of schema files I'm trying to register is the following.

mathml2.xsd
|
--- common-attrib.xsd
|
--- math.xsd

"mathml2.xsd" is a root schema file
"common-attrib.xsd" defines one attributeGroup
"math.xsd" references the attributeGroup defined in "common-attrib.xsd"


When I try to register these schema files, an error says,

==============================================
SQL> call dbms_xmlschema.registerSchema
2 (
3 'common-attribs.xsd',
4 xdbURIType('/home/pattern1/common-attribs.xsd').getClob()
5 );

Call completed.

SQL>
SQL> call dbms_xmlschema.registerSchema
2 (
3 'math.xsd',
4 xdbURIType('/home/pattern1/math.xsd').getClob()
5 );
call dbms_xmlschema.registerSchema
*

ORA-31154: invalid XML document
ORA-19202: Error occurred in XML processing
LSX-00024: unknown attribute group "Common.attrib"
ORA-06512: "XDB.DBMS_XMLSCHEMA_INT", line0
ORA-06512: "XDB.DBMS_XMLSCHEMA", line26
ORA-06512: line1
==============================================


A SQL code and schema files I used are the following:

register.sql ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Set echo on
alter session Set events='31098 trace name context forever';

call dbms_xmlschema.registerSchema
(
'common-attribs.xsd',
xdbURIType('/home/pattern1/common-attribs.xsd').getClob()
);

call dbms_xmlschema.registerSchema
(
'math.xsd',
xdbURIType('/home/pattern1/math.xsd').getClob()
);

call dbms_xmlschema.registerSchema
(
'mathml2.xsd',
xdbURIType('/home/pattern1/mathml2.xsd').getClob()
);


common-attribs.xsd ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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

<xs:schema
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns="http://www.w3.org/1998/Math/MathML"
xmlns:xlink="http://www.w3.org/1999/xlink"
targetNamespace="http://www.w3.org/1998/Math/MathML"
elementFormDefault="qualified"
>

<xs:attributeGroup name="Common.attrib">
<xs:attribute name="style" type="xs:string"/>
</xs:attributeGroup>

</xs:schema>


math.xsd ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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

<xs:schema
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns="http://www.w3.org/1998/Math/MathML"
targetNamespace="http://www.w3.org/1998/Math/MathML"
elementFormDefault="qualified"
>

<xs:attributeGroup name="math.attlist">
<xs:attributeGroup ref="Common.attrib"/>
</xs:attributeGroup>

<xs:complexType name="math.type">
<xs:attributeGroup ref="math.attlist"/>
</xs:complexType>

<xs:element name="math" type="math.type"/>

</xs:schema>


mathml2.xsd ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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

<xs:schema
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns="http://www.w3.org/1998/Math/MathML"
targetNamespace="http://www.w3.org/1998/Math/MathML"
elementFormDefault="qualified"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>

<xs:include schemaLocation="math.xsd"/>
<xs:include schemaLocation="common-attribs.xsd"/>

</xs:schema>


Actually, what I want to do is to register MathML.
Do I need some options to register such a pattern?
Please help me><
Any comments will be appreciated.

* version: Oracle9i Enterprise Edition Release 9.2.0.4.0 - Production