Download the most current, fully patched version.
The script below, with your commands in it,
runs fine in my version.
Steve
units lj
atom_style atomic
lattice fcc 0.8442
region box block 0 5 0 5 0 5
create_box 1 box
create_atoms 1 box
mass 1 1.0
velocity all create 1.44 87287 loop geom
pair_style lj/cut 2.5
pair_coeff 1 1 1.0 1.0 2.5
neighbor 0.3 bin
neigh_modify delay 0 every 20 check no
fix 1 all nve
thermo_style custom step temp pe pzz
thermo 1000
fix 2 all ave/time 1 1000 1000 c_thermo_press[2]
run 10000