Perl 5.8 is very old. Whether that’s the problem I don’t know; but when I add a line defining $hostname to the code you posted:

#! perl
use strict;
use warnings;
use Socket qw(:addrinfo SOCK_RAW);

my $hostname = 'perlmonks.pair.com';

my ($err, @res) = getaddrinfo($hostname, "", { socktype => SOCK_RAW })
+;
die "Cannot getaddrinfo - $err" if $err;

while (my $ai = shift @res)
{
    my ($err, $ipaddr) = getnameinfo($ai->{addr}, NI_NUMERICHOST, NIx_
+NOSERV);
    die "Cannot getnameinfo - $err" if $err;

    print "$ipaddr\n";
}
[download]

it works correctly on my system:

22:41 >perl 1602_SoPW.pl
209.197.123.153

22:42 >
[download]

(Windows 8.1 64-bit, Strawberry Perl 5.22.1, Socket v2.021.)

Hope that helps,