Yey Another "NRPE: Unable to read output"

Having this message with a debian plugin, I have tried a minimum example 
: plugin on the "client" in a /home/nagios :


nagios@server:/home/nagios$ ls -lh
total 8.0K
-rwxrwxrwx 1 nagios nagios 48 Mar  8 07:08 check_bash
-rwxrwxrwx 1 nagios nagios 73 Mar 10 09:26 check_pl
nagios@server:/home/nagios$ cat check_bash
#!/bin/bash

     echo "CRITICAL-pc "
     exit 2
nagios@server:/home/nagios$ cat check_pl
#!/usr/bin/perl
#
#
#
use strict;
print STDERR "CRITICAL-pc\n";
exit(2);
nagios@server:/home/nagios$ ./check_pl
CRITICAL-pc
nagios@server:/home/nagios$ echo $?
2
nagios@server:/home/nagios$ ./check_bash
CRITICAL-pc
nagios@server:/home/nagios$ echo $?
2

When executed on the nagios "server" :

root@nagios:~# /usr/lib/nagios/plugins/check_nrpe  -H 192.168.163.1 -c 
check_bash
CRITICAL-pc
root@nagios:~# /usr/lib/nagios/plugins/check_nrpe  -H 192.168.163.1 -c 
check_pl
NRPE: Unable to read output

What do I miss ....?

Why perl (or  python...) plugin does not work ?

Thanks for any help

PC