OK well, I figured out a solution that is congruent with HTML template side of things, but I'm still unable to access the search array of @files. It's almost as it's unable to search via the CGI request ...
Oh well, here's the updated code

 sub _update_realtime_radial_file_list {

    my $self        = shift;
    my $stations    = shift;

    # deconstruct $stations and rebuild into arrays
    my (@ids,@codenames);
    foreach my $station (@{$stations}) {
        push @ids, $station->{id};
        push @codenames, $station->{codename};
    }

    # remote host
    my $hostname = 'xxx.xxx.xxx.xxx';
    my $username = 'xxxxx';
    my $password = 'xxxxxxxxxxx';
    my $Dbase    = '/data/archive/real-time/staging/radial';

    # time
    my ($sc,$mn,$hr,$md,$mo,$yr,$wd,$yd,$id) = localtime(time); $yr +=
+ 1900; $mo += 1;
    my $now = sprintf('%4d-%02d-%02d %02d:%02d:%02d',$yr,$mo,$md,$hr,$
+mn,$sc);

    # connect
    use Net::SFTP::Foreign;
    my $sftp = Net::SFTP::Foreign->new( $hostname , user => $username 
+, password => $password ) or fatal_error($!);

    # search
    my @latestfiles = ();
    my $flatest;
    foreach my $station ( @{$stations} ) {

        my $Dsearch = $Dbase.'/'. $station->{codename}.'/'.$yr;
        my @files   = $sftp->find( $Dsearch , wanted => sub{
                                       use Fcntl qw(S_ISREG);
                                       my $now            = time();
                                       my $yesterday      = $now-(24*3
+600);
                                       my (undef, $entry) = @_;
                                       ( ($entry->{a}->mtime < $now) a
+nd ($entry->{a}->mtime > $yesterday) and S_ISREG($entry->{a}->perm) )
                                   } );
        $flatest = $_->{filename} for $files[-1];
        push @latestfiles, $flatest;

    }

    # create table output
    my @table_data = ();
    while ( @ids and @codenames and @latestfiles ) {
        my %row_data;
        $row_data{id} = shift @ids;
        $row_data{codename} = shift @codenames;
        $row_data{flatest} = shift @latestfiles;
        push @table_data, \%row_data;
    }

    # TEMPLIFY!
    my $template = $self->load_tmpl('show_radial_file_status.tmpl');
    $template->param( title    => "Latest Files on ACORN Server",
                      now      => $now,
                      hostname => $hostname,
                      table     => \@table_data,
                    );


    $sftp->disconnect;
    return $template->output();

}
[download]

which results in:
There has been an error: Modification of non-creatable array value attempted, subscript -1 at /users/dpath2o/sites/simple_secure/simple_realtime/simple_realtime.pm line 172.

You are getting that error because @files is empty - you should really check it before trying to access.

my @files = ();
my $flatest = $_->{filename} for $files[-1];

Modification of non-creatable array value attempted, subscript -1
[download]