Adding use strict back in and cleaning up the resulting compile errors, I was able to get it to work.

use warnings;
use strict;

use Win32::PerfLib;

my %counter;
my $server = "";

Win32::PerfLib::GetCounterNames($server, \%counter);

my %r_counter = map { $counter{$_} => $_ } keys %counter;

# retrieve the id for process object
my $process_obj = $r_counter{Process};
# retrieve the id for the process ID counter
my $process_id = $r_counter{'ID Process'};

# create connection to $server
my $perflib = new Win32::PerfLib($server);
my $proc_ref = {};

# get the performance data for the process object
$perflib->GetObjectList($process_obj, $proc_ref);
$perflib->Close();

my $instance_ref = $proc_ref->{Objects}->{$process_obj}->{Instances};
foreach my $p (sort keys %{$instance_ref}) {
    my $counter_ref = $instance_ref->{$p}->{Counters};
    foreach my $i (keys %{$counter_ref}) {
        if($counter_ref->{$i}->{CounterNameTitleIndex} == $process_id)
+ {
            printf( "% 6d %s\n", $counter_ref->{$i}->{Counter},
                    $instance_ref->{$p}->{Name}
                  );
        }
    }
}
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Update: Dog and Pony has identified that the code is not the problem. See this node for info.

--
May the Source be with you.

You said you wanted to be around when I made a mistake; well, this could be it, sweetheart.