CSOM Javascript FolderUrl not Working

Hi All

I'm trying to add an Item to a Folder. My problem is that the record always goes to the main root. I'm missing what?

var ctx = new SP.ClientContext(siteUrl);
var list = ctx.get_web().get_lists().getByTitle("LIST");

var itemCreateInfo = new SP.ListItemCreationInformation();
itemCreateInfo.FolderUrl = "http://URL/Lists/LIST/FOLDER";
alert(itemCreateInfo.FolderUrl);
this.litem = list.addItem(itemCreateInfo);

Thanks