i have a problem in thermal conductivity computing

Dear lammps user’s
i try to compute thermal conductivity of ZnO system using the ReaxFF potential included in lammps distribution and i have used the script giving in the lammps manuals for Ar with some modifications:
the input file is the next:

units real

variable V equal vol
variable T equal 300
variable dt equal 0.5

variable p equal 200 # correlation length
variable s equal 10 # sample interval
variable d equal $p*$s # dump interval

convert from LAMMPS real units to SI

variable kB equal 1.3806504e-23 # [J/K] Boltzmann
variable kCal2J equal 4186.0/6.02214e23
variable A2m equal 1.0e-10
variable fs2s equal 1.0e-15
variable convert equal {kCal2J}*{kCal2J}/{fs2s}/{A2m}

setup problem

dimension 3
boundary p p p

atom_style charge
read_data data.ZnOH2

pair_style reax/c lmp_control
pair_coeff * * ffield.reax.ZnOH O Zn

neighbor 0.5 bin
neigh_modify every 1 delay 0 check no
#timestep 0.5

timestep ${dt}
thermo 10

equilibration and thermalization

velocity all create $T 102486 mom yes rot yes dist gaussian

fix NVT all nvt temp $T $T 60 drag 0.0
fix 2 all qeq/reax 1 0.0 10.0 1e-6 reax/c #param.qeq

run 2000

thermal conductivity calculation, switch to NVE if desired

#unfix NVT
#fix NVE all nve

reset_timestep 0
compute myKE all ke/atom
compute myPE all pe/atom
compute myStress all stress/atom virial
compute flux all heat/flux myKE myPE myStress
variable Jx equal c_flux[1]/vol
variable Jy equal c_flux[2]/vol
variable Jz equal c_flux[3]/vol
fix JJ all ave/correlate $s $p d & c_flux[1] c_flux[2] c_flux[3] type auto file J0Jt.dat ave running variable scale equal {convert}/${kB}/$T/$T/$V*s*{dt}

variable k11 equal trap(f_JJ[3]){scale} variable k22 equal trap(f_JJ[4])*{scale}
variable k33 equal trap(f_JJ[5])
thermo_style custom step temp v_Jx v_Jy v_Jz v_k11 v_k22 v_k33

run 400000

variable k equal (v_k11+v_k22+v_k33)/3.0
variable ndens equal count(all)/vol
print “average conductivity: $k[W/mK] @ T K, {ndens} /A^3”

for equilibration part thereis no problem and the code run just fine however for the second part which is reserved to thermal conductivity computing the run stop with the next message:

ERROR: fix in variable not computed at compatible time (…/variable.cpp/3173)

so please if any one has a solution let me know
best regards

From doc/Section errors.html:

*Fix in variable not computed at compatible time*
Fixes generate their values on specific timesteps. The variable is requesting the values on a non-allowed timestep.
Your fix ave/correlate only generates values on certain timesteps (see its doc page). Your variable
that uses it, is violating that restriction, hence the error message.