error message

Hello:
These days, I am trying to investigate a triple system co-li-Zn. I was very confused that when I run runstruct_vasp, an error message always appeared. It read "/POTCAR.Z: No such file or directoryot/paw_pbe/Co" when I run this command in directory 2.
The lat.in file was:
2.5 2.5 4.0 90 90 120

 1 0 0 

 0 1 0 

 0 0 1

 0.333333333         0.666666667         0.250000000 Zn,Li,Co

 0.666666667         0.333333333         0.750000000 Zn,Li,Co

vasp.wrap file was:
[INCAR]
PREC = high
ISPIN=2
NSW=500
ENCUT = 500
ISMEAR = 1
SIGMA = 0.1
IBRION = 2
ISIF = 3
KPPRA = 1000
USEPOT = PAWPBE
DOSTATIC
MAGATOM=
The str.out file in the directory 2 was :
2.500000 0.000000 0.000000
-1.250000 2.165064 0.000000
0.000000 0.000000 4.000000
1.000000 0.000000 0.000000
0.000000 1.000000 0.000000
0.000000 0.000000 1.000000
0.333333 0.666667 0.250000 Co
0.666667 0.333333 0.750000 Co

the vasp.out.relax file in the directory 2 was:
running on 1 nodes
distr: one band on 1 nodes, 1 groups
vasp.5.2.12 26May11 complex
POSCAR found : 1 types and 2 ions
ERROR: number of potentials on File POTCAR incompatible with number of species
INCAR : 1 POTCAR: 0

The error message was :
mana1974@ubuntu:~/software/work-atat/2$ runstruct_vasp
/POTCAR.Z: No such file or directoryot/paw_pbe/Co
tail: +: invalid number of lines
mana1974@ubuntu:~/software/work-atat/2$ Finding best cluster expansion…
done!
It seemed that there was no POTCAR.Z file in the corresponding directory. However, in fact, POTCAR.Z file did exist in that directory.

mana1974@ubuntu:~/software/vasp/pot/paw_pbe/Co$ ls
DDE.Z POTCAR POTCAR.Z PSCTR.Z V_RHFIN.Z V_TABIN.Z
mana1974@ubuntu:~/software/vasp/pot/paw_pbe/Co$

Interestingly, when I substituted the element Ca for Co in an example provided by the atat website. It can be run without any errors.
This example was :
4.1 4.1 4.1 90 90 90
0 0.5 0.5
0.5 0 0.5
0.5 0.5 0
0 0 0 Co,Mg
0.5 0.5 0.5 O

mana1974@ubuntu:~/software$ cd work-atat4
mana1974@ubuntu:~/software/work-atat4$ maps -d &
[3] 39553
mana1974@ubuntu:~/software/work-atat4$ touch ready
mana1974@ubuntu:~/software/work-atat4$ Finding best structure…
done!
cd 0
mana1974@ubuntu:~/software/work-atat4/0$ runstruct_vasp
mana1974@ubuntu:~/software/work-atat4/0$ Finding best cluster expansion…
done!

The str.out file in directory 0 was:
4.100000 0.000000 0.000000
0.000000 4.100000 0.000000
0.000000 0.000000 4.100000
0.500000 -0.000000 0.500000
0.500000 0.500000 0.000000
0.000000 0.500000 0.500000
1.000000 1.000000 1.000000 Co
0.500000 0.500000 0.500000 O

Therefore, I really wanted to know where this error came from and how to solve it.
Can you help me with that?

It looks like you may have some invisible characters in your input file (the garbled line
"/POTCAR.Z: No such file or directoryot/paw_pbe/Co" is a hint of that).
The see these characters, do

cat -v lat.in

This may happen if you use a windows-based text editor instead of a unix-based one (emacs, vi, etc.)