Problems in build the schemas.jar from the AddressBook example

[Sy...@aol.com]

I try to run the AddressBook example and build the schemas.jar using ANT 
myself.

I got the following error saying addressBook.xsd contactUsa.xsd is not a 
schema file:

But I just unzip the schema files from AddrBookSchemas.zip  . I appreciate if 
you can give me any pointer.

Buildfile: C:\workspace\xmlSandbox\xmlbeans\build.xml
  [xmlbean] Time to build schema type system: 0.782 seconds
  [xmlbean] Time to generate code: 0.0 seconds
  [xmlbean] Compiled types to C:\workspace\xmlSandbox\xmlbeans\Schemas.jar
  [xmlbean] ERROR: C:\workspace\xmlSandbox\xmlbeans\schema\addressBook.xsd: 
Document C:\workspace\xmlSandbox\xmlbeans\schema\addressBook.xsd is not a 
schema file (Error code: 1)
  [xmlbean] ERROR: C:\workspace\xmlSandbox\xmlbeans\schema\contactUsa.xsd: 
Document C:\eworkspace\xmlSandbox\xmlbeans\schema\contactUsa.xsd is not a schema 
file (Error code: 1)
BUILD FAILED: C:\workspace\xmlSandbox\xmlbeans\build.xml:9: null
Total time: 2 seconds

Here is my ANT file:

In case you need my ant.xml file, here is it:
<?xml version="1.0"?>

<project basedir="." default="xmlbean">

    <taskdef name="xmlbean"
   
             classname="com.bea.xbean.tool.XMLBean"
             classpath="lib/xmlbeans.jar"
     />
    <xmlbean  
    schema="schema" destfile="Schemas.jar"/>

</project>