How to recognise/get current window

Presently am using below code, and it is showing an error message says "Cannot call method "getCurrentWindow" of undefined (<Unknown source>#4) in <Unknown source> at line number 4"

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function insertDataIntoHtmlEditorIE()
{

currentwindow = this.browserbot.getCurrentWindow(this);

var iFrame = currentwindow.getElementById

('ctl00_MainContent_editor_ctl02_ctl00');

var iFrameBody;

iFrameBody =

iFrame.contentWindow.document.getElementsByTagName('body')[0];

iFrameBody.innerHTML = "xyz";

}
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please help me out to resolve this issue..
*am calling this script in Selenium RC through Eclipse

You haven't defined this.browserbot inside that function? Are you sure that it exists?