See if you at least can connect.

#!/usr/bin/perl -w
use strict;
use Net::SFTP;

# Net::SFTP does no error reporting
my $sftp = undef;

eval{
$sftp = Net::SFTP->new("hostnumber", 
                    user=>"me",
            password=>"mypass",
            );
};
if ($@) { print "Sftp connection failed:\n  $@\n"; }

if (! $sftp) {
  print "I can't connect!\n";
}else{
  print "SUCCESS!\n";
}
[download]

If you can connect, it is likely you get permission denied because the file you seek is not in the directory that you think you are in. Try the fullpathname to the file.

If you can't connect, try Net::SSH2. See A little demo for Net::SSH2 for how to sftp thru it.