Take a look at your usage of the -textvariable attribute, I belive the snippet below does what you want.

use strict;
use warnings;

use Tk;

my ($name, $frame, $entry);
my $main = MainWindow->new();
my $frameEntry = $main->Frame()->grid();

$entry = $frameEntry -> Entry(-textvariable => \$name)->grid(-column =
+> 1, -row => 5);

$name = "Updated after";

MainLoop;
[download]

-Nitrox