diff --git a/account_invoice_constraint_chronology/model/account_invoice.py b/account_invoice_constraint_chronology/model/account_invoice.py
index b964b13e9..63b8e454f 100644
--- a/account_invoice_constraint_chronology/model/account_invoice.py
+++ b/account_invoice_constraint_chronology/model/account_invoice.py
@@ -31,6 +31,7 @@ from openerp import models, api, fields
 from openerp.tools.translate import _
 from openerp.tools import DEFAULT_SERVER_DATE_FORMAT
 from datetime import datetime
+from openerp import exceptions
 
 
 class account_invoice(models.Model):
@@ -54,12 +55,11 @@ class account_invoice(models.Model):
                                   DEFAULT_SERVER_DATE_FORMAT)
                     date_invoice_tz = fields\
                         .Date.context_today(self, date_invoice_format)
-                    raise models.except_orm(_('Error !'),
-                                            _("Chronology Error!"
-                                              " Please confirm older draft"
-                                              " invoices before %s and"
-                                              " try again.") %
-                                            date_invoice_tz)
+                    raise exceptions.Warning(_("Chronology Error!"
+                                               " Please confirm older draft"
+                                               " invoices before %s and"
+                                               " try again.") %
+                                             date_invoice_tz)
 
                 if inv.internal_number is False:
                     invoices = self.search([('state', 'in', ['open', 'paid']),
@@ -73,10 +73,9 @@ class account_invoice(models.Model):
                                       DEFAULT_SERVER_DATE_FORMAT)
                         date_invoice_tz = fields\
                             .Date.context_today(self, date_invoice_format)
-                        raise models.except_orm(_('Error !'),
-                                                _("Chronology Error! There"
-                                                  " exist at least one invoice"
-                                                  " with a date posterior"
-                                                  " to %s.") %
-                                                date_invoice_tz)
+                        raise exceptions.Warning(_("Chronology Error! There"
+                                                   " exist at least one"
+                                                   " invoice with a date"
+                                                   " posterior to %s.") %
+                                                 date_invoice_tz)
         return res
diff --git a/account_invoice_constraint_chronology/tests/test_account_constraint_chronology.py b/account_invoice_constraint_chronology/tests/test_account_constraint_chronology.py
index 8c7c4f366..04cf60091 100644
--- a/account_invoice_constraint_chronology/tests/test_account_constraint_chronology.py
+++ b/account_invoice_constraint_chronology/tests/test_account_constraint_chronology.py
@@ -29,7 +29,7 @@
 
 import openerp.tests.common as common
 from openerp import workflow
-from openerp.osv import orm
+from openerp import exceptions
 from datetime import datetime, timedelta
 from openerp.tools import DEFAULT_SERVER_DATE_FORMAT
 
@@ -106,7 +106,7 @@ class TestAccountConstraintChronology(common.TransactionCase):
         create_simple_invoice(self, journal_id, date)
         date = today.strftime(DEFAULT_SERVER_DATE_FORMAT)
         invoice_2 = create_simple_invoice(self, journal_id, date)
-        self.assertRaises(orm.except_orm, workflow.trg_validate, self.uid,
+        self.assertRaises(exceptions.Warning, workflow.trg_validate, self.uid,
                           'account.invoice', invoice_2.id, 'invoice_open',
                           self.cr)
 
@@ -120,7 +120,7 @@ class TestAccountConstraintChronology(common.TransactionCase):
                               'invoice_open', self.cr)
         date = today.strftime(DEFAULT_SERVER_DATE_FORMAT)
         invoice_2 = create_simple_invoice(self, journal_id, date)
-        self.assertRaises(orm.except_orm, workflow.trg_validate, self.uid,
+        self.assertRaises(exceptions.Warning, workflow.trg_validate, self.uid,
                           'account.invoice', invoice_2.id, 'invoice_open',
                           self.cr)
 
@@ -131,6 +131,6 @@ class TestAccountConstraintChronology(common.TransactionCase):
         date = yesterday.strftime(DEFAULT_SERVER_DATE_FORMAT)
         create_simple_invoice(self, journal_id, date)
         invoice_2 = create_simple_invoice(self, journal_id, False)
-        self.assertRaises(orm.except_orm, workflow.trg_validate, self.uid,
+        self.assertRaises(exceptions.Warning, workflow.trg_validate, self.uid,
                           'account.invoice', invoice_2.id, 'invoice_open',
                           self.cr)