I user openerp8 on ubuntu server. Installed successfully hr_recruitment. I create successfully "incoming HR applicant ". But there is another problem when opening an Applicant from Recruitment -> Application there is an error message below

OpenERP Server Error

Traceback (most recent call last): File "/usr/lib/pymodules/python2.7/openerp/http.py", line 434, in dispatch response["result"] = self._call_function(*self.params) File "/usr/lib/pymodules/python2.7/openerp/http.py", line 295, in _call_function return checked_call(self.db, *args, *kwargs) File "/usr/lib/pymodules/python2.7/openerp/service/model.py", line 113, in wrapper return f(dbname, args, *kwargs) File "/usr/lib/pymodules/python2.7/openerp/http.py", line 292, in checked_call return self.endpoint(a, *kw) File "/usr/lib/pymodules/python2.7/openerp/http.py", line 635, in __call__ return self.method(args, *kw) File "/usr/lib/pymodules/python2.7/openerp/http.py", line 338, in response_wrap response = f(args, *kw) File "/usr/lib/pymodules/python2.7/openerp/addons/web/controllers/main.py", line 1226, in call_kw return self._call_kw(model, method, args, kwargs) File "/usr/lib/pymodules/python2.7/openerp/addons/web/controllers/main.py", line 1218, in _call_kw return getattr(request.registry.get(model), method)(request.cr, request.uid, args, *kwargs) File "/usr/lib/pymodules/python2.7/openerp/addons/mail/mail_message.py", line 604, in message_read self._message_read_dict_postprocess(cr, uid, message_list, message_tree, context=context) File "/usr/lib/pymodules/python2.7/openerp/addons/mail/mail_message.py", line 354, in _message_read_dict_postprocess attachments = ir_attachment_obj.read(cr, SUPERUSER_ID, list(attachment_ids), ['id', 'datas_fname', 'name', 'file_type'], context=context) File "/usr/lib/pymodules/python2.7/openerp/addons/base/ir/ir_attachment.py", line 283, in read return super(ir_attachment, self).read(cr, uid, ids, fields_to_read, context, load) File "/usr/lib/pymodules/python2.7/openerp/osv/orm.py", line 3295, in read result = self._read_flat(cr, user, select, fields, context, load) File "/usr/lib/pymodules/python2.7/openerp/osv/orm.py", line 3411, in _read_flat res2 = self._columns[f].get(cr, self, ids, f, user, context=context, values=res) File "/usr/lib/pymodules/python2.7/openerp/osv/fields.py", line 1225, in get elif result.get(id):

AttributeError: 'str' object has no attribute 'get'

how to fix it?