No such file or directory: 'cdata/snli/train.tok.forvocab'

what's train.tok.forvocab ? Could i replace it as "train.txt" ?

You can create train.tok.forvocab using nliutils.conver_data(), just adapting
print(' ||| '.join([text['gold_label'], text['sentence1'], text['sentence2']]), file = dout) as print(' '.join(text['sentence1'], text['sentence2']]), file = dout)