After I restored the database on a server that I thought has the same installation there was an error. The database loaded. But the menu on the left side wasn't available anymore.

How to solve this?

OpenERP Server Error Client Traceback (most recent call last): File "/var/packages/OpenERP6.1/target/openerp/addons/web/common/http.py", line 180, in dispatch response["result"] = method(controller, self, **self.params) File "/var/packages/OpenERP6.1/target/openerp/addons/web/controllers/main.py", line 746, in load return {'data': self.do_load(req)} File "/var/packages/OpenERP6.1/target/openerp/addons/web/controllers/main.py", line 788, in do_load menu_ids = Menus.search([], 0, False, False, context) File "/var/packages/OpenERP6.1/target/openerp/addons/web/common/openerplib/main.py", line 250, in proxy args, kw) File "/var/packages/OpenERP6.1/target/openerp/addons/web/common/openerplib/main.py", line 117, in proxy result = self.connector.send(self.service_name, method, *args) File "/var/packages/OpenERP6.1/target/openerp/addons/web/common/http.py", line 611, in send raise fault

Server Traceback (most recent call last): File "/var/packages/OpenERP6.1/target/openerp/addons/web/common/http.py", line 592, in send result = openerp.netsvc.dispatch_rpc(service_name, method, args) File "/usr/local/lib/python2.7/site-packages/openerp/netsvc.py", line 360, in dispatch_rpc result = ExportService.getService(service_name).dispatch(method, params) File "/usr/local/lib/python2.7/site-packages/openerp/service/web_services.py", line 572, in dispatch res = fn(db, uid, params) File "/usr/local/lib/python2.7/site-packages/openerp/osv/osv.py", line 167, in execute_kw return self.execute(db, uid, obj, method, *args, *kw or {}) File "/usr/local/lib/python2.7/site-packages/openerp/osv/osv.py", line 121, in wrapper return f(self, dbname, args, *kwargs) File "/usr/local/lib/python2.7/site-packages/openerp/osv/osv.py", line 176, in execute res = self.execute_cr(cr, uid, obj, method, args, *kw) File "/usr/local/lib/python2.7/site-packages/openerp/osv/osv.py", line 164, in execute_cr return getattr(object, method)(cr, uid, args, *kw) File "/var/packages/OpenERP6.1/target/openerp/addons/base/ir/ir_ui_menu.py", line 123, in search result = self._filter_visible_menus(cr, uid, ids, context=context) File "/var/packages/OpenERP6.1/target/openerp/addons/base/ir/ir_ui_menu.py", line 99, in _filter_visible_menus if not menu.child_id: File "/usr/local/lib/python2.7/site-packages/openerp/osv/orm.py", line 476, in __getattr__ return self[name] File "/usr/local/lib/python2.7/site-packages/openerp/osv/orm.py", line 391, in __getitem__ field_values = self._table.read(self._cr, self._uid, ids, field_names, context=self._context, load="_classic_write") File "/usr/local/lib/python2.7/site-packages/openerp/osv/orm.py", line 3381, in read result = self._read_flat(cr, user, select, fields, context, load) File "/usr/local/lib/python2.7/site-packages/openerp/osv/orm.py", line 3504, in _read_flat res2 = self._columns[f].get(cr, self, ids, f, user, context=context, values=res) File "/usr/local/lib/python2.7/site-packages/openerp/osv/fields.py", line 551, in get ids2 = obj.pool.get(self._obj).search(cr, user, self._domain + [(self._fields_id, 'in', ids)], limit=self._limit, context=context) File "/var/packages/OpenERP6.1/target/openerp/addons/base/ir/ir_ui_menu.py", line 123, in search result = self._filter_visible_menus(cr, uid, ids, context=context) File "/var/packages/OpenERP6.1/target/openerp/addons/base/ir/ir_ui_menu.py", line 99, in _filter_visible_menus if not menu.child_id: File "/usr/local/lib/python2.7/site-packages/openerp/osv/orm.py", line 476, in __getattr__ return self[name] File "/usr/local/lib/python2.7/site-packages/openerp/osv/orm.py", line 391, in __getitem__ field_values = self._table.read(self._cr, self._uid, ids, field_names, context=self._context, load="_classic_write") File "/usr/local/lib/python2.7/site-packages/openerp/osv/orm.py", line 3381, in read result = self._read_flat(cr, user, select, fields, context, load) File "/usr/local/lib/python2.7/site-packages/openerp/osv/orm.py", line 3504, in _read_flat res2 = self._columns[f].get(cr, self, ids, f, user, context=context, values=res) File "/usr/local/lib/python2.7/site-packages/openerp/osv/fields.py", line 551, in get ids2 = obj.pool.get(self._obj).search(cr, user, self._domain + [(self._fields_id, 'in', ids)], limit=self._limit, context=context) File "/var/packages/OpenERP6.1/target/openerp/addons/base/ir/ir_ui_menu.py", line 123, in search result = self._filter_visible_menus(cr, uid, ids, context=context) File "/var/packages/OpenERP6.1/target/openerp/addons/base/ir/ir_ui_menu.py", line 99, in _filter_visible_menus if not menu.child_id: File "/usr/local/lib/python2.7/site-packages/openerp/osv/orm.py", line 476, in __getattr__ return self[name] File "/usr/local/lib/python2.7/site-packages/openerp/osv/orm.py", line 391, in __getitem__ field_values = self._table.read(self._cr, self._uid, ids, field_names, context=self._context, load="_classic_write") File "/usr/local/lib/python2.7/site-packages/openerp/osv/orm.py", line 3381, in read result = self._read_flat(cr, user, select, fields, context, load) File "/usr/local/lib/python2.7/site-packages/openerp/osv/orm.py", line 3504, in _read_flat res2 = self._columns[f].get(cr, self, ids, f, user, context=context, values=res) File "/usr/local/lib/python2.7/site-packages/openerp/osv/fields.py", line 551, in get ids2 = obj.pool.get(self._obj).search(cr, user, self._domain + [(self._fields_id, 'in', ids)], limit=self._limit, context=context) File "/var/packages/OpenERP6.1/target/openerp/addons/base/ir/ir_ui_menu.py", line 123, in search result = self._filter_visible_menus(cr, uid, ids, context=context) File "/var/packages/OpenERP6.1/target/openerp/addons/base/ir/ir_ui_menu.py", line 95, in _filter_visible_menus if not modelaccess.check(cr, uid, data[field], 'read', False): File "/usr/local/lib/python2.7/site-packages/openerp/tools/cache.py", line 18, in lookup r = self.lookup(self2, cr, *args) File "/usr/local/lib/python2.7/site-packages/openerp/tools/cache.py", line 46, in lookup value = d[args] = self.method(self2, cr, *args) File "/var/packages/OpenERP6.1/target/openerp/addons/base/ir/ir_model.py", line 509, in check if self.pool.get(model_name).is_transient(): AttributeError: 'NoneType' object has no attribute 'is_transient'