Traceback (most recent call last):
  File "/trytond/protocols/jsonrpc.py", line 108, in _marshaled_dispatch
    response['result'] = dispatch_method(method, params)
  File "/trytond/protocols/jsonrpc.py", line 147, in _dispatch
    res = dispatch(*args)
  File "/trytond/protocols/dispatcher.py", line 155, in dispatch
    res = getattr(obj, method)(*args_without_context, **kargs)
  File "/trytond/wizard/wizard.py", line 120, in execute
    action_res = getattr(self, action)(data)
  File "/trytond/ir/module/module.py", line 523, in _upgrade_module
    pool.init(update=True, lang=lang)
  File "/trytond/pool.py", line 118, in init
    lang=lang)
  File "/trytond/modules/__init__.py", line 430, in load_modules
    load_module_graph(graph, pool, lang)
  File "/trytond/modules/__init__.py", line 227, in load_module_graph
    obj.init(module)
  File "/trytond/modules/account_product/product.py", line 77, in init
    super(CategoryCustomerTax, self).init(module_name)
  File "/trytond/model/modelsql.py", line 142, in init
    ref = pool.get(field.model_name)._table
  File "/trytond/pool.py", line 135, in get
    return self._pool[self.database_name][type][name]
KeyError: 'account.tax'