diff --git a/addons/mrp/mrp.py b/addons/mrp/mrp.py
index c4a4d8df895..e814cc33df5 100644
--- a/addons/mrp/mrp.py
+++ b/addons/mrp/mrp.py
@@ -620,7 +620,7 @@ class mrp_production(osv.osv):
                     self.write(cr, uid, [production.id], {'bom_id': bom_id, 'routing_id': routing_id})
 
             if not bom_id:
-                raise osv.except_osv(_('Error'), _("Couldn't find a bill of material for this product."))
+                raise osv.except_osv(_('Error'), _("Cannot find a bill of material for this product."))
             factor = uom_obj._compute_qty(cr, uid, production.product_uom.id, production.product_qty, bom_point.product_uom.id)
             res = bom_obj._bom_explode(cr, uid, bom_point, factor / bom_point.product_qty, properties, routing_id=production.routing_id.id)
             results = res[0]
@@ -643,7 +643,7 @@ class mrp_production(osv.osv):
         for production in self.browse(cr, uid, ids, context=context):
             if production.state == 'confirmed' and production.picking_id.state not in ('draft', 'cancel'):
                 raise osv.except_osv(
-                    _('Could not cancel manufacturing order !'),
+                    _('Cannot cancel manufacturing order.'),
                     _('You must first cancel related internal picking attached to this manufacturing order.'))
             if production.move_created_ids:
                 move_obj.action_cancel(cr, uid, [x.id for x in production.move_created_ids])
diff --git a/addons/mrp/wizard/change_production_qty.py b/addons/mrp/wizard/change_production_qty.py
index e85ceda7dd5..36f31dceae8 100644
--- a/addons/mrp/wizard/change_production_qty.py
+++ b/addons/mrp/wizard/change_production_qty.py
@@ -80,12 +80,12 @@ class change_production_qty(osv.osv_memory):
                 if not bom_point:
                     bom_id = bom_obj._bom_find(cr, uid, prod.product_id.id, prod.product_uom.id)
                     if not bom_id:
-                        raise osv.except_osv(_('Error'), _("Couldn't find bill of material for product"))
+                        raise osv.except_osv(_('Error'), _("Cannot find bill of material for product."))
                     prod_obj.write(cr, uid, [prod.id], {'bom_id': bom_id})
                     bom_point = bom_obj.browse(cr, uid, [bom_id])[0]
 
                 if not bom_id:
-                    raise osv.except_osv(_('Error'), _("Couldn't find bill of material for product"))
+                    raise osv.except_osv(_('Error'), _("Cannot find bill of material for product."))
 
                 factor = prod.product_qty * prod.product_uom.factor / bom_point.product_uom.factor
                 res = bom_obj._bom_explode(cr, uid, bom_point, factor / bom_point.product_qty, [])
diff --git a/addons/mrp_operations/mrp_operations.py b/addons/mrp_operations/mrp_operations.py
index cab7a109991..34220196f91 100644
--- a/addons/mrp_operations/mrp_operations.py
+++ b/addons/mrp_operations/mrp_operations.py
@@ -513,7 +513,7 @@ class mrp_operations_operation(osv.osv):
                  code_lst.append(oper.code_id.start_stop)
             if code.start_stop=='start':
                     if 'start' in code_lst:
-                        raise osv.except_osv(_('Sorry!'),_('Operation has already started !' 'Youcan either Pause/Finish/Cancel the operation'))
+                        raise osv.except_osv(_('Sorry!'),_('Operation has already started !' 'You can either Pause/Finish/Cancel the operation.'))
                         return False
             if code.start_stop=='pause':
                     if  code_lst[len(code_lst)-1]!='resume' and code_lst[len(code_lst)-1]!='start':