error in lammps input script

Dear Axel and users,
Thank you for your valued response.
As ur suggestion, I worked on these but still get the similar types of errors.

I am trying to run the GCMC simulation of a rigid and fixed mof structure to adsrob CO2 molecules. In simulation, the UFF/DREIDING inter-atomic parameters are used for MOF along with a three-site model parameter for CO2 (TraPPE). which pair coefficients carried data of UFF data. I just used the TraPPE parameters given in example/gcmc/CO2.txt.

I am using the lammps-23oct2017 version.

Previously we ran GCMC successfully for the same MOF system with the single site methane model and it ran smoothly without any errors. Whenever I replaced the single site methane gas molecule with the three site CO2 molecule by above way, it is giving errors. Initially, because ch4 molecule was chargeless and it had pair_coeff for 1 atom type. Now, we have pair_coeff for two atom types, C & O of CO2. apart from MOF 4 atom types parameters (Cu, C, O, and H). The error output is printed below:

LAMMPS (23 Oct 2017)
Reading data file …
orthogonal box = (-11.4157 -11.4157 -11.4157) to (25.3415 25.3415 25.3415)
1 by 1 by 1 MPI processor grid
reading atoms …
374 atoms
Finding 1-2 1-3 1-4 neighbors …
special bond factors lj: 0 0 0
special bond factors coul: 0 0 0
0 = max # of 1-2 neighbors
0 = max # of 1-3 neighbors
0 = max # of 1-4 neighbors
1 = max # of special neighbors
ERROR: No count or invalid atom count in molecule file (…/molecule.cpp:490)
Last command: molecule gas gas2.molecule offset 4 0 0 0 0 # molecule templates

find the attachment below of gas2.molecule as well as input script

3 atoms
0 bonds
0 angles


1 0.0 0.0 0.0
2 -1.16 0.0 0.0
3 1.16 0.0 0.0

1 5
2 6
3 6


1 0.7
2 -0.35
3 -0.35

My input script is -

units real
dimension 3
boundary p p p
atom_style full
atom_modify map array
pair_style lj/cut 12.5


molecule gas gas2.molecule offset 4 0 0 0 0 # offset for 4 atom types present in the MOF

well, obviously your molecule file does not conform with the requirements for that kind of file, while the provided file in the GCMC example does.

it should not require much effort to compare the two and both with the documentation of the molecule file format. the LAMMPS manual has a reputation for meticulously describing all details, often to the point of being confusing to a superficial reader. so please re-read it very carefully. the error message gives a strong hint of what is wrong.