_pickle.UnpicklingError: invalid load key, 'v'.

[violet2274]

iter 283217 (epoch 24), train_loss = 1.939, time/batch = 0.101
Traceback (most recent call last):
File "train.py", line 275, in
train(opt)
File "train.py", line 146, in train
init_scorer(opt.cached_tokens)
File "D:\01\misc\rewards.py", line 23, in init_scorer
CiderD_scorer = CiderD_scorer or CiderD(df=cached_tokens)
File "D:\01\cider\pyciderevalcap\ciderD\ciderD.py", line 28, in init
self.cider_scorer = CiderScorer(n=self._n, df_mode=self._df)
File "D:\01\cider\pyciderevalcap\ciderD\ciderD_scorer.py", line 82, in init
pkl_file = cPickle.load(open(os.path.join('data', df_mode + '.p'),'rb'), **(dict(encoding='latin1') if six.PY3 else {}))
_pickle.UnpicklingError: invalid load key, 'v'.
This problem appears in every trained model, how to solve it?