getting validation error

File "/mnt/extra-addons/insight_merchant_base/models/res_users.py", line 22, in create
    raise ValidationError(_("Sorry !! You cannot create more users"))
odoo.tools.convert.ParseError: "Sorry !! You cannot create more users


my xml file.
 <record model="res.partner" id="partner_manager">
        <field name="name">Manager</field>
        <field name="company_id" ref="base.main_company"/>
        <!--<field name="customer" eval="False"/>-->
        <field name="email">manager@example.com</field>
        <!--<field name="image" type="base64" file="base/static/img/avatar.png"/>-->
    </record>

    <!-- user 3 is the human Manager user -->
    <record id="pk_user_manager" model="res.users">
         <field name="name">manager</field>
        <field name="login">manager</field>
        <field name="password">manager</field>
        <field name="partner_id" ref="partner_manager"/>
        <field name="company_id" ref="base.main_company"/>
        <field name="company_ids" eval="[(4, ref('base.main_company'))]"/>
        <field name="groups_id" eval="[(4, ref('point_of_sale.group_pos_manager')), (4, ref('stock.group_stock_user'))]"/>
        <field name="signature"><![CDATA[<span>-- <br/>
Manager</span>]]></field>
    </record>