Mirotik queue change through API

I was implementing time based queue change. Rather than using mikrotik in-built scheduler i thought to execute a crontab through central location. Therefore i tried with except scripting but with telnet it failed or not working properly. I think the returned results might have any color coding input. while searching i stumble on the mikrotik perl api written by Hugh [URL:http://forum.mikrotik.com/viewtopic.php?f=8&t=22744].
i just edited the example code as follows. this is the upgrade this will be edited for the download.

#!/usr/bin/perl -w
#to define the api. 
BEGIN {push @INC, '/root/upgradefolder'}
use Mtik ;

$mtik_host =  "192.168.28.49";
$mtik_user =  "user_script";
$mtik_passwd = "passwordscript";
my(@cmd);
push(@cmd,"/queue/simple/set");
push(@cmd,"=limit-at=6144000/6144000");
push(@cmd,"=max-limit=6144000/6144000");
push(@cmd,"=.id=2M");

$Mtik::debug = 0;
if (Mtik::login($mtik_host,$mtik_user,$mtik_passwd)) {
      my($retval,@results) = Mtik::raw_talk(\@cmd);
      foreach my $result (@results) {
        print ">>> $result\n";
      }
  Mtik::logout();
}
else {
  print "Couldn't log in to $mtik_host\n";
}

Mikrotik side I've enabled api services.

 ip service print
Flags: X - disabled, I - invalid
 #   NAME                  PORT  ADDRESS            CERTIFICATE
 0   telnet                23    0.0.0.0/0
 1   ftp                   21    0.0.0.0/0
 2   www                   80    0.0.0.0/0
 3   ssh                   22    0.0.0.0/0
 4 X www-ssl               443   0.0.0.0/0          none
 5   api                   8728  0.0.0.0/0
 6   winbox                8291  0.0.0.0/0

and named the queue as 2M

>queue simple print
Flags: X - disabled, I - invalid, D - dynamic
 0    name="2M" target-addresses=192.168.28.48/29 dst-address=0.0.0.0/0
      interface=ether3 parent=none direction=both priority=8
      queue=default-small/default-small limit-at=4096000/4096000
      max-limit=4096000/4096000 burst-limit=0/0 burst-threshold=0/0
      burst-time=0s/0s total-queue=default-small

And added the crontab according to it .

#Auto bandwidth upgrade script
01 19 * * * /root/upgradefolder/test_upgrade.pl
01 07 * * 1-5 /root/upgradefolder/test_downgrade.pl