I added a new submenu in the main menu "human resources" under the sub-menu "contracts". The sub-menu appears but the problem is when I click on the link of this module it shows me a KeyError error message: u'ir.actions.act_window '. How can I solve this problem? .Any help please?

traceback

  Traceback (most recent call last):
  File "D:\Projet_Odoo\odoo-8.0-20171009\openerp\http.py", line 546, in _handle_exception
   return super(JsonRequest, self)._handle_exception(exception)
  File "D:\Projet_Odoo\odoo-8.0-20171009\openerp\http.py", line 583, in dispatch
   result = self._call_function(**self.params)
 File "D:\Projet_Odoo\odoo-8.0-20171009\openerp\http.py", line 319, in _call_function
return checked_call(self.db, *args, **kwargs)
 File "D:\Projet_Odoo\odoo-8.0-20171009\openerp\service\model.py", line 118, in wrapper
  return f(dbname, *args, **kwargs)
File "D:\Projet_Odoo\odoo-8.0-20171009\openerp\http.py", line 316, in checked_call
return self.endpoint(*a, **kw)
File "D:\Projet_Odoo\odoo-8.0-20171009\openerp\http.py", line 812, in __call__
return self.method(*args, **kw)
File "D:\Projet_Odoo\odoo-8.0-20171009\openerp\http.py", line 412, in response_wrap
response = f(*args, **kw)
File "D:\Projet_Odoo\odoo-8.0-20171009\openerp\addons\web\controllers\main.py", line 1247, in load
action = request.session.model(action_type).read([action_id], False, ctx)
File "D:\Projet_Odoo\odoo-8.0-20171009\openerp\http.py", line 913, in proxy
mod = request.registry[self.model]
File "D:\Projet_Odoo\odoo-8.0-20171009\openerp\modules\registry.py", line 102, in __getitem__
return self.models[model_name]
KeyError: u'ir.actions.act_window '

payroll_per_hour_view.xml

<?xml version="1.0" encoding="UTF-8"?>

<openerp>
<data>
 <record id="action_payroll_hour_form" model="ir.actions.act_window">
    <field name="res_model">hr.contract</field>
    <field name="view_type">form</field>
    <field name="name">Grille de prix d'heure</field>
    <field name="view_mode">tree,form</field>
    <field name="type">ir.actions.act_window </field>
</record>
   <menuitem id="menu_payroll_per_hour" name="Grille d'heure" parent="hr.menu_hr_main"  action="action_payroll_hour_form" sequence="10"/>

</data>
</openerp>