Cluster size distribution

Dear LAMMPS Users
We are trying to simulate the dipolar LJ particles in two dimensions to study the aggregation behaviours as function of temperature and number of particles. For this we need to calculate cluster size distribution. We have used “cluster/atom” key to evaluate this but some how it is working and showing following
ERROR: Illegal compute cluster/atom command (…/compute_cluster_atom.cpp:40)
fix 3 all ave/histo 100 1 100 0 20 20 c_size mode vector ave running beyond ignore file tmp.histo

Please suggest the way to rectify this. I am also attaching my script used for this.

Point dipoles in a 2d box

units lj
atom_style hybrid sphere dipole
dimension 2
boundary p p p

lattice sq2 0.3
region box block 0 10 0 10 -0.5 0.5
create_box 1 box
create_atoms 1 box

need both mass settings due to hybrid atom style

mass 1 1.0
set group all mass 1.0
set group all dipole/random 98934 1

velocity all create 0.0 87287 mom no

pair_style lj/cut/dipole/cut 1.122 46
pair_coeff * * 1.0 1.0

neighbor 0.3 bin
neigh_modify delay 0

fix 1 all nvt/sphere temp 1.0 1.0 0.01 disc update dipole
fix 2 all enforce2d

timestep 0.001

compute erot all erotate/sphere
compute syTem all temp/sphere
thermo_style custom step temp epair c_erot etotal press
thermo 500

compute cluster all cluster/atom 1.2
compute cc1 all chunk/atom c_cluster compress yes
compute size all property/chunk cc1 count
fix 3 all ave/histo 100 1 100 0 20 20 c_size mode vector ave running beyond ignore file tmp.histo

dump 1 all custom 100 dump.dipole01* id type x y z mux muy

#dump 1 all image 250 image.*.jpg mux type &

zoom 1.6 adiam 1.2

#dump_modify 1 pad 5

run 100000

Thanks.
regards

Manish