The handle is invalid.
Error communicating with PsExec service on Blah.Blah.Blah

##</code><code>##

cmd started on Blah.Blah.Blah with process ID 4428.
##</code><code>##

print for qx|$externalExe 2>&1|;

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;

my @servers = qw(
	Blah.Blah.Blah 
	Blah1.Blah.Blah 
	Blah2.Blah.Blah
	Blah3.Blah.Blah
	Blah4.Blah.Blah
);

foreach (@servers){

my $externalExe = qq(psexec.exe \\\\$_ );
$externalExe .= q(-u BLAH\foo -p secret -i -d cmd /c shutdown /r /f /t 0);

print "\n\nStarting external program...\n";

print for qx|$externalExe 2>&1|; # Executes the program, and prints it's output 

print "Program $externalExe run completed.\n";
sleep 360;

}