The problematic part is this one:

  foreach my $subnet (($ip->bits() == 32)?@IPv4Subnets:@IPv6Subnets)
  {
    next if ($subnet eq '');
    my @subnetInfo = split(/;/x, $subnet);
    if (Net::CIDR::cidrlookup($params{ip}, trim($subnetInfo[0])))
    {
      return (1, \@subnetInfo);
    }
  }
[download]

I have also tried to rewrite it to while cycle with the same result.

  my $number = 0;
  my @subnets = ($ip->bits() == 32)?@IPv4Subnets:@IPv6Subnets;
  while ($number < scalar @subnets) {
      my $subnet = @subnets[$number];
      if ($subnet eq '') {
          $number++;
          next;
      }
      my @subnetInfo = split(/;/x, $subnet);
      if (Net::CIDR::cidrlookup($params{ip}, trim($subnetInfo[0]))) {
          return (1, \@subnetInfo);
      }
      else {
          $number++;
      }
  }
  return (0, "Could not find ip '$params{ip}' in subnets list");
[download]

Funnily enough the script worked when I had incorrect comparison operator ($subnet == '') in my code (with a lot of complaining from Perl of course)