Error in th multigpu-nce-rnnlm.lua

[adonisues]

I have this error when when running example "th multigpu-nce-rnnlm.lua "

th multigpu-nce-rnnlm.lua --tiny --progress

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loading cached /root/data/BillionWords/train_tiny.cache.t7
loading cached /root/data/BillionWords/valid_data.cache.t7
loading cached /root/data/BillionWords/test_data.cache.t7
Vocabulary size : 793471
Train set split into 32 sequences of length 32550
/local/sshwang/torch/torch/install/bin/luajit: /local/sshwang/torch/torch/install/share/lua/5.1/nn/GPU.lua:23: attempt to call method 'find' (a nil value)
stack traceback:
/local/sshwang/torch/torch/install/share/lua/5.1/nn/GPU.lua:23: in function '__init'
...sshwang/torch/torch/install/share/lua/5.1/torch/init.lua:91: in function <...sshwang/torch/torch/install/share/lua/5.1/torch/init.lua:87>
[C]: in function 'GPU'
multigpu-nce-rnnlm.lua:104: in main chunk
[C]: in function 'dofile'
...orch/torch/install/lib/luarocks/rocks/trepl/scm-1/bin/th:145: in main chunk
[C]: at 0x00406670

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My GPU Settings

nvcc -V
nvcc: NVIDIA (R) Cuda compiler driver
Copyright (c) 2005-2015 NVIDIA Corporation
Built on Tue_Aug_11_14:27:32_CDT_2015
Cuda compilation tools, release 7.5, V7.5.17

lspci | grep -i nvidia
06:00.0 3D controller: NVIDIA Corporation GK210GL [Tesla K80] (rev a1)
07:00.0 3D controller: NVIDIA Corporation GK210GL [Tesla K80] (rev a1)
84:00.0 3D controller: NVIDIA Corporation GK210GL [Tesla K80] (rev a1)
85:00.0 3D controller: NVIDIA Corporation GK210GL [Tesla K80] (rev a1)

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Thank you.