Hi everyone, I'm trying to migrate my database from 7.0 to 8.0 but I have an error with module stock, I reviewed the tables and it seems that the data has been migrated well but always got the following error:

Error context:
View `stock.picking.form`
[view_id: 679, xml_id: stock.view_picking_form, model: stock.picking, parent_id: n/a]
2015-02-05 16:45:00,097 15501 CRITICAL fruti78 openerp.service.server: Failed to initialize database `fruti78`.
Traceback (most recent call last):
  File "/home/dago-gallo/Development/odoo/8.0/OpenUpgrade/openerp/service/server.py", line 901, in preload_registries
    registry = RegistryManager.new(dbname, update_module=update_module)
  File "/home/dago-gallo/Development/odoo/8.0/OpenUpgrade/openerp/modules/registry.py", line 324, in new
    openerp.modules.load_modules(registry._db, force_demo, status, update_module)
  File "/home/dago-gallo/Development/odoo/8.0/OpenUpgrade/openerp/modules/loading.py", line 490, in load_modules
    if not Views._validate_custom_views(cr, SUPERUSER_ID, model):
  File "/home/dago-gallo/Development/odoo/8.0/OpenUpgrade/openerp/api.py", line 237, in wrapper
    return old_api(self, *args, **kwargs)
  File "/home/dago-gallo/Development/odoo/8.0/OpenUpgrade/openerp/addons/base/ir/ir_ui_view.py", line 1116, in _validate_custom_views
    return self._check_xml(cr, uid, ids)
  File "/home/dago-gallo/Development/odoo/8.0/OpenUpgrade/openerp/api.py", line 237, in wrapper
    return old_api(self, *args, **kwargs)
  File "/home/dago-gallo/Development/odoo/8.0/OpenUpgrade/openerp/addons/base/ir/ir_ui_view.py", line 206, in _check_xml
    view_def = self.read_combined(cr, uid, view.id, None, context=context)
  File "/home/dago-gallo/Development/odoo/8.0/OpenUpgrade/openerp/api.py", line 237, in wrapper
    return old_api(self, *args, **kwargs)
  File "/home/dago-gallo/Development/odoo/8.0/OpenUpgrade/openerp/addons/base/ir/ir_ui_view.py", line 563, in read_combined
    cr, uid, arch_tree, view_arch, parent_view['id'], context=context)
  File "/home/dago-gallo/Development/odoo/8.0/OpenUpgrade/openerp/api.py", line 237, in wrapper
    return old_api(self, *args, **kwargs)
  File "/home/dago-gallo/Development/odoo/8.0/OpenUpgrade/openerp/addons/base/ir/ir_ui_view.py", line 505, in apply_inheritance_specs
    self.raise_view_error(cr, uid, _("Element '%s' cannot be located in parent view") % tag, inherit_id, context=context)
  File "/home/dago-gallo/Development/odoo/8.0/OpenUpgrade/openerp/api.py", line 237, in wrapper
    return old_api(self, *args, **kwargs)
  File "/home/dago-gallo/Development/odoo/8.0/OpenUpgrade/openerp/addons/base/ir/ir_ui_view.py", line 390, in raise_view_error
    raise AttributeError(message)
AttributeError: Element '<xpath expr="/form/header//button[@name='draft_force_assign']">' cannot be located in parent view

View image here: https://drive.google.com/a/clearcorp.co.cr/file/d/0B8NblWSNGrfKV2xaR3k1MkQ1Qkk/view

Hope somebody can helpme, thanks.