push @myhosts, 'mymail01';
  push @myhosts, 'mymail02';

  foreach my $mypc (@myhosts) {
  for (my $i = 0; $i < 256; $i++) {
    my $bucket  = sprintf('%02x', $i);
    my $file    = sprintf('%s/%s/%02x.db', $qdir, $mypc, $i);

    tie (my %hash, 'DB_File', $file, O_RDWR, 0600) || next;
    foreach my $key ( keys %hash ) {

        if (!defined $hash{$key}) {
           print "$key not defined\n";
           delete($hash{$key});
           untie %hash;
           exit 1;
        }

       # $type\t$d$t\t$size\t$from\t$to\t$subj\t$score
       my @tmp       = split /\t/, $hash{$key}, 7;
       my $type      = $tmp[0];
       my $dt        = $tmp[1];
       my ($year, $month, $day) = $dt =~ m|(\d{4})(\d{2})(\d{2})T.*|;
       printf("bucket: %s\ttype: %s\t%s-%s-%s\t%s\n",$bucket,$type,$year,$month,$day,$dt)

    }
    untie %hash;

##</code><code>##

bucket: aa      type: spam      2012-07-07      20120707T204829
spam-aa0b162b5118763a9f053d1412f9f0b1-20120705T082627-27218-15.gz not defined
Use of uninitialized value within %hash in concatenation (.) or string at ./list_hash.pl line 66.