Sorting with aoColumns and type

socialink

I have the following table declared, but its not ordering by the 4th column (or the 3rd, for that matter, as the "order" parameter doesnt seem to work). Any tips?

`var pmTablesSortable = $('table.datatable').dataTable( {
         "sDom": "<'row'<'span8'l><'span8'f>r>t<'row'<'span8'i><'span8'p>>",
         "order": [[ 4, "desc" ]],
        "bFilter": true,
        "bAutoWidth": false,
         "aoColumns": [
                        null,
                        null,
                        null,
                        null,
                        { "sType": 'currency' },
                        null,
                        null,
                        null
                    ]

    } );`