[5.0] Error cuando genero factura XML y la factura no tiene fecha, ni numero de factura

Manda el siguiente error.

Environment Information :
System : Windows-32bit
OS Name : nt
Operating System Release :
Operating System Version : 32bit
Operating System Architecture : 32bit
Operating System Locale : es_MX.cp1252
Python Version : 2.5.1
OpenERP-Client Version : 5.0.15
Last revision No. & ID :Bazaar Package not Found !Traceback (most recent call last):
  File "C:\svn_moylop260\server\bin\netsvc.py", line 299, in dispatch
    result = LocalService(service_name)(method, *params)
  File "C:\svn_moylop260\server\bin\netsvc.py", line 77, in __call__
    return getattr(self, method)(*params)
  File "C:\svn_moylop260\server\bin\service\web_services.py", line 634, in execute
    return self._execute(db, uid, wiz_id, datas, action, context)
  File "C:\svn_moylop260\server\bin\service\web_services.py", line 614, in _execute
    return wiz.execute(db, uid, self.wiz_datas[wiz_id], action, context)
  File "C:\svn_moylop260\server\bin\wizard\__init__.py", line 178, in execute
    res = self.execute_cr(cr, uid, data, state, context)
  File "C:\svn_moylop260\server\bin\wizard\__init__.py", line 73, in execute_cr
    action_res = action(self, cr, uid, data, context)
  File "C:\svn_moylop260\server\bin\addons\l10n_mx_facturae\wizard\wizard_invoice_facturae_xml.py", line 64, in _get_invoice_facturae_xml
    fname, xml_data = invoice_obj._get_facturae_invoice_xml_data(cr, uid, ids, context=context)
  File "C:\svn_moylop260\server\bin\addons\l10n_mx_facturae\invoice.py", line 641, in _get_facturae_invoice_xml_data
    sign_str = self._get_sello(cr=False, uid=False, ids=False, context=context)
  File "C:\svn_moylop260\server\bin\addons\l10n_mx_facturae\invoice.py", line 757, in _get_sello
    year = float( time.strftime('%Y', time.strptime(fecha, '%Y-%m-%dT%H:%M:%S')) )
  File "C:\Python25\lib\_strptime.py", line 330, in strptime
    (data_string, format))
ValueError: time data did not match format: data= fmt=%Y-%m-%dT%H:%M:%S