Can you a complete script?

Something like this:

use strict;
use Net::SSH::Perl;
my $ssh = Net::SSH::Perl->new('my_host') or die "$!";
$ssh->login('my_user', 'my_password');
my ($stdout, $stderr, $exit) = $ssh->cmd('ls');
print "$stdout";
[download]

Try specifying "protocol => 2" or "cipher => 'blowfish-cbc'".