Why would you need IO::Socket::INET
Would not the following suffice.

my $dir='/whatever';
use Net::FTP;

my $ftp = Net::FTP->new("severname fqdn")|| die("Could not connect: $@
+\n");
$ftp->login("user","password")||die("Wrong username or password "
);
        $ftp->binary();
        $ftp->cwd("$dir")||die("Could not change path ");
        #@aa=$ftp->ls("$dir");
        $ftp->get("$file_name")|| die("File not found $file_name\n");
        $ftp->quit;
[download]

That should do it
Regards,
Rajdeep