Row details assign DOM object and not html

I'm trying to get the example from the forums to work

http://www.datatables.net/forums/discussion/2812/row-details-assign-dom-object-and-not-html/p1

var nNew = oTable.fnOpen( nTr, '' );
nNew.getElementsByTagName('td')[0].appendChild( MyDiv );

I keep getting an error:
Uncaught Error: NotFoundError: DOM Exception 8