Error - Nested metadata in DSpace items

[IBARU TICS S.A.S]

I need to store a group of information related to the author, (department); and I'm configuring these files:

1.   input-forms.xml

       <field>

                 <dc-schema>dc</dc-schema>

         <dc-element>contributor</dc-element>

         <dc-qualifier>author</dc-qualifier>

         <repeatable>true</repeatable>

         <label>Authors</label>

         <input-type>onebox</input-type>

         <hint>Enter the names of the authors of this item in the form Surname, Firstname [i.e. Smith, Josh or Smith, J].</hint>

         <required></required>

       </field>

        <field>

                 <dc-schema>dc</dc-schema>

          <dc-element>contributor</dc-element>

          <dc-qualifier>department</dc-qualifier>

          <label>Grupo Investigacion</label>

          <input-type>onebox</input-type>

          <repeatable>true</repeatable>

          <parent>dc.contributor.author</parent>

          <required></required>

          <hint>Enter Grupo de Investigacion  for each author.</hint>

        </field>

       <field>

2. cris-authority-metadatagenerator.xml

        <bean id="org.dspace.app.cris.integration.RPExtraAuthorityMetadataGenerator"

        class="org.dspace.app.cris.integration.RPExtraAuthorityMetadataGenerator">

        <property name="relatedInputformMetadata" value="dc.contributor.department"/>

        <property name="schema" value="affiliation"/>

        <property name="element" value="affiliationorgunit"/>

                <property name="qualifier" value="name"/>

                USE THE FOLLOW PROPERTY WITH RPMultiAuthority implementation (see RPMultiAuthority)

                <property name="singleResultOnAggregate" value="false"/>

     </bean>

What can be wrong?

Thanks

David.