this is the error !! any reponse please

attrs['selection'] = relation._name_search(cr, user, '', dom, context=search_context, limit=None, name_get_uid=1) AttributeError: 'NoneType' object has no attribute '_name_search' 2014-05-01 10:51:54,340 8443 ERROR base openerp.tools.convert: Parse error in /opt/openerp/v7/modules-openerp/event/report/report_event_registration_view.xml:45:

<record model="ir.ui.view" id="view_report_event_registration_search">
            <field name="name">report.event.registration.search</field>
            <field name="model">report.event.registration</field>
            <field name="arch" type="xml">
                <search string="Event on Registration">
                    <filter icon="terp-document-new" string="New" domain="[('event_state','=','draft')]" help="Events which are in New state"/>
                    <filter icon="terp-check" string="Confirm" domain="[('event_state','=','confirm')]" help="Events which are in confirm state"/>
                    <separator/>
                    <filter icon="terp-personal" string="My Events" help="My Events" domain="[('user_id','=',uid)]"/>
                    <field name="event_id" string="Event"/>
                    <field name="user_id"/>
                    <group expand="0" string="Extended Filters...">
                        <field name="event_type" widget="selection"/>
                        <field name="event_date"/>
                    </group>
                    <newline/>
                    <group expand="1" string="Group By...">
                        <filter string="Participant / Contact" icon="terp-personal" context="{'group_by':'name_registration'}" help="Registration contact"/>
                        <filter string="Register" icon="terp-personal" context="{'group_by':'user_id_registration'}" help="Registration contact" groups="base.group_no_one"/>
                        <filter string="Speaker" name="speaker" icon="terp-personal+" context="{'group_by': 'speaker_id'}" groups="base.group_no_one"/>
                        <filter string="Event Responsible" name="user_id" icon="terp-personal" context="{'group_by': 'user_id'}"/>
                        <filter string="Event" name="event" icon="terp-crm" context="{'group_by':'event_id', 'max_reg_event_visible':0}"/>
                        <filter string="Event Type" icon="terp-crm" context="{'group_by':'event_type'}"/>
                        <filter string="Event State" icon="terp-stock_effects-object-colorize" context="{'group_by':'event_state'}"/>
                        <filter string="Registration State" icon="terp-stock_effects-object-colorize" context="{'group_by':'registration_state'}"/>
                        <filter string="Company" icon="terp-go-home" domain="[]" context="{'group_by':'company_id'}" groups="base.group_multi_company"/>
                        <filter string="Day" icon="terp-go-month" domain="[]" context="{'group_by':'event_date'}" help="Event Beginning Date"/>
                        <filter string="Month" icon="terp-go-month" domain="[]" context="{'group_by':'month'}" help="Event Beginning Date"/>
                        <filter string="Year" icon="terp-go-year" domain="[]" context="{'group_by':'year'}" help="Event Beginning Date"/>
                    </group>
                    <group expand="0" string="Display">
                        <filter icon="terp-camera_test" string="Show Confirmed Registrations" help="Registrations in confirmed or done state" context="{'no_of_draft_invisible':1}"/>
                    </group>
                </search>
            </field>
        </record>