my %args =(ssh_args => { user     =>'XXXX',
           identity_files  => [ '/home/myhome/zzz.private' ],
                               }
);

my $targetserver='file.yyy.net';
my $sftp = Net::SFTP->new($targetserver, %args) or die "could not open connection to $targetserver\n";

##</code><code>##

"Not an ARRAY reference at /usr/lib/perl5/site_perl/5.8.1/Net/SFTP.pm line 36."