use strict;
use warnings;

use Encode qw( encode decode );

sub fix_broken_text {
    my ($self, $field) = @_;
    $field = decode('cp1252', $field);
    $field =~ s/&/&/g;
    $field =~ s/</&lt;/g;
    $field =~ s/>/&gt;/g;
    $field =~ s/"/&quot;/g;
    $field =~ s/'/&#39;/g;
    $field = encode('UTF-8', $field);
    return $field;
}

my $encoded_xml;
{
   open(my $fh, '<', $xml_qfn) or die;
   binmode($fh);
   local $/;
}

...Try to fix problems with unescaped characters...

...Pass $encoded_xml to parser...