Cannot make multimedia_saveSettingsString work

[Vishwas-G]

I referred to this thread:

https://forums.adobe.com/thread/1634466

And here is my sample code.

import flash.events.Event;

var result:Object = ExternalInterface.call("multimedia_loadSettingsString");

if (result)

{

a_Tf.text = String(result.toString());

}

a_Sb.addEventListener(MouseEvent.CLICK, clickit);

function clickit(e:Event):void

{

    trace('hello');

    a_Tf.text = String(100);

    var result:Object = ExternalInterface.call("multimedia_saveSettingsString",a_Tf.text);

}

Dropbox - adobe-forum-question-files

Can anyone help me understand, what am I doing wrong?  Why doesn't it work?