Paragraph level: preprocess data

[wentsun12]

I met the following error when I tried to process the paragraph level data. I have no idea about how to use Lua or correct. Could anyone give some advices?

preprocess.lua -config config-preprocess

Building source vocabulary...
Created dictionary of size 45004 (pruned from 71333)

Building target vocabulary...
Created dictionary of size 28003 (pruned from 35366)

Building prgrph vocabulary...
Created dictionary of size 45004 (pruned from 87180)

Preparing training data...
... shuffling sentences
... sorting sentences by size
/usr/bin/lua: preprocess.lua:162: bad argument #1 to 'pairs' (table expected, got userdata)
stack traceback:
[C]: in function 'pairs'
preprocess.lua:162: in function 'vecToTensor'
preprocess.lua:270: in function 'makeData'
preprocess.lua:321: in function 'main'
preprocess.lua:354: in main chunk
[C]: ?