If I use single quotes, I get the error "Can't call method "login" on an undefined value at line x." Here's the relevant portion of the code:

use Net::FTP;

my ($ftp, $host, $user, $pass, $dir, $fpath);

$host = 'ftp.my.com';
$user = 'last.first@somewhere.com';
$pass = 'mypass';
$dir = '/my/file_path/onftp';

$fpath = 'myfileonserver_xml.zip';

$ftp = Net::FTP->new($host, Debug => 0);
$ftp->login($user, $pass) || die $ftp->message;  ##this is line x##
$ftp->cwd($dir);
$ftp->put($fpath) || die $ftp->message;
$ftp->quit;
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