my $remote_file = $ftp->put($name) || die $ftp->message;
means
my $remote_file = ( $ftp->put($name) || die $ftp->message );

my $remote_file = $ftp->put($name) or die $ftp->message;
means
( my $remote_file = $ftp->put($name) ) or die $ftp->message;

Both are fine here.