save_model parameter not found

[fooSynaptic]

while i try to save model train with sgd the error rise:

../bin/libFM -task c -train sampleRatingData.dat.libfm -test sampleRatingData.dat.libfm -dim ’1,1,8’ -out sample.res -rlog sample.log -method sgd -learn_rate 0.001 -regular '0,0,0.001' -save_model model.fm 
----------------------------------------------------------------------------
libFM
  Version: 1.4.2
  Author:  Steffen Rendle, [email protected]
  WWW:     http://www.libfm.org/
This program comes with ABSOLUTELY NO WARRANTY; for details see license.txt.
This is free software, and you are welcome to redistribute it under certain
conditions; for details see license.txt.
----------------------------------------------------------------------------

ERROR: the parameter save_model does not exist

Some people claim the model can saved by sgm-trained model with save_model flag, how to fix this?