nytprof generates error messages with this code

gistfile1.pl

#!/usr/bin/perl

use v5.14;
use warnings;
use utf8::all;
use autodie;

open my $source, '<', 'dracula.txt';

foreach my $line (<$source>) {
  print $line if ((index substr($line, 0, 1), 'T') == 0);
}

close $source;