Is that the whole script? You need to assign values to some $scon objects. www.perldoc.org has examples of how to use this. Spend a few minutes over there.
use strict;
use Net::SSH::W32Perl;
my $host = 'server123.com123.domain123.com';
my $scon = new Net::SSH::W32Perl($host, (protocol=>'2',port=>'22',debug=>'true'));
$scon->login("user123","pass123");
print "looking around ...\n";
my ($out, $err, $exit) = $scon->cmd('ls');
print "done";