don't work tag field in inherit view

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OpenERP 6.1

In documantation said that for add new field in inherit view need use follow code:
<record model="ir.ui.view" id="view_partner_form">
    <field name="name">res.partner.form.inherit</field>
    <field name="model">res.partner</field>
    <field name="inherit_id" ref="base.view_partner_form"/>
    <field name="arch" type="xml">
        <notebook position="inside">
            <page string="Relations">
                <field name="relation_ids" colspan="4" nolabel="1"/>
            </page>
        </notebook>
    </field>
</record>

But if i use it i get Error:
ValidateError
Error occurred while validating the field(s) arch: Invalid XML for View Architecture!

If i use tag xpath for located new field then it work but only in gtk-client, web-client get error like this:

uncaught exception: The key ,,filed was not found
:0

with xpath i must use full path to tag path and how i can located with xpath anonymous group? For example, i need add some field in hr_employee.view_employee_form to "Contact Information" but this group hav't attribute string/name, that mean i can't located it with <xpath expr="/form/notebook/page[@string='Personal Information']/group[@string'SOME GROUP NAME']/field[@string='Office Location']" position="after">

Have any way out?