This works for me on windows:

use warnings;
use strict;
use Net::SFTP::Foreign;

my $host = 'xxx.xxx.xxx.xxx';
my $user = 'user';
my $pass = 'pass';
my $file = 'whatever';
my $contents;

my $sftp = Net::SFTP::Foreign->new
          ($host,
            backend => 'Net_SSH2',
            username => $user,
            password => $pass);

$sftp->error and
  die "Unable to establish SFTP connection: "
      . $sftp->error;

$sftp->get($file, "foo.txt")
  or die "get failed: " . $sftp->error;

open RD, '<', "foo.txt" or die $!;
while (<RD>) {$contents .= $_}
close RD or die "$!";

print $contents;

unlink "foo.txt";
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It needs both Net::SSH2 and Net::SFTP::Foreign.

Cheers,
Rob

UPDATE: Or, to get it (more) directly into a scalar, we can do this (or something similar):

use warnings;
use strict;
use Net::SFTP::Foreign;

my $host = 'xxx.xxx.xxx.xxx';
my $user = 'user';
my $pass = 'pass';
my $file = 'whatever';
my $contents;

my $sftp = Net::SFTP::Foreign->new
          ($host,
            backend => 'Net_SSH2',
            username => $user,
            password => $pass);

$sftp->error and
  die "Unable to establish SFTP connection: "
      . $sftp->error;

close STDOUT;
open STDOUT, '>', \$contents or die "Can't open STDOUT: $!";

$sftp->get($file, \*STDOUT) or die "get failed: " . $sftp->error;

warn $contents;
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