when i am running compare.py. i am getting this error.

Traceback (most recent call last):
  File "compare_1.py", line 32, in ?
  File "/usr/lib/modeller9v8/modlib/modeller/alignment.py", line 329, in malign3d
_modeller.ModellerError: fit2xyz_296E> Number of equivalent positions < 3:        1

in this particular i am taking 12 template to making alignment.ali . but as soon as when i am starting with two, three, means any random number of template to make my alignment.ali its working.