why is this trying to create a column called '0'?

// initialise dataTables
	var oTable = $('#example').dataTable( {
		"sScrollY": "410px",
		"bPaginate": false,
		"bProcessing": true,
		"bAutoWidth": false,
		"bScrollCollapse": false,
		"aoColumns": [
			{ "mdata": "id","bVisible": false, "bSortable": false, sTitle:"id" },
   			{ "mData": "n", "sDefaultContent": "Edit", sTitle : "Room Name" },
   			{ "mData": "b", "sDefaultContent": "Edit", sTitle : "Building" },   			
   			{ "mData": "c", "sDefaultContent": "Edit", sTitle : "Campus" },
   			{ "mData": "floor", "sDefaultContent": "Edit", sTitle : "Floor" },   			
   			{ "mData": "department", "sDefaultContent": "Edit", sTitle : "Department" },
   			{ "mData": "lab", "sDefaultContent": "Edit", sTitle : "Lab" },
   			{ "mData": "lecture", "sDefaultContent": "Edit", sTitle : "Lec" },
   			{ "mData": "tutorial", "sDefaultContent": "Edit", sTitle : "Tut" },
   			{ "mData": "contents", "sDefaultContent": "Edit", sTitle : "Contents"} ]
	});

		TRoom = new Object;
		TRoom.id = 21;
		TRoom.n = 'fred';
		TRoom.b ='building';
		TRoom.c ='campus';
		TRoom.floor='fllor';
		TRoom.department='dep';
		TRoom.lab=1;
		TRoom.lecture=2;
		TRoom.tutorial=3;
		TRoom.contents='cont';
		$('#example').dataTable().fnAddData( TRoom );