I had missed to connect to the server. Now i made changes to my code as bellow:

use Win32::TieRegistry(Delimiter => "/", ArrayValues => 0);

$host = "myserver.com";
$password='password';
$domain='myserver';
$login = 'my_admin';
$op=`net use \\\\$host\\ipc\$ \"$password\" \/user:$domain\\$login`;
$remoteKey = $Registry->{"//$host/LMachine/SOFTWARE/Microsoft/Windows 
+NT/CurrentVersion/ProductName"} or die "Can't read from $host. Error:
+ $^E\n";
print "$remoteKey\n";
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Now I am getting the perfect output.