my $orig_IRS = $/;    # save the original input record separator
$/ = "\x00";

while (<$ORIG>) {

  $count = (($change = $_)
         =~ s/(\x33\x33\x39\x39.*?\x00)/"\x00" x length($1)/e);

  if ($count == null) {
    print $MOD $_;

  } else {

    local $/ = $orig_IRS;  # restore input record separator locally

    $answer = &promptUser("Modify $1?");
    if ($answer == "y") {
      print $MOD $change;
    } else {
      print $MOD $_;
    }
  }