TypeError

Hello all. I'm getting my info from a database, and I get the error TypeError: undefined is not an object (evaluating 'j[k].style').
Here is the code ajax code I'm using

$(document).ready(function() {
            var table = $('#example').DataTable( {
                "ajax": "includes/payroll.php",
                "columns": [
                    {
                        "className":      'details-control',
                        "orderable":      false,
                        "data":           null,
                        "defaultContent": ''
                    },
                    { "data": "empNum" },
                    { "data": "empName" },
                    { "data": "appFlag"},
                    { "data": "unitRate" },
                    { "data": "salary" },
                    { "data": "hourly"},
                    { "data": "appr1"},
                    { "data": "appr2"},
                    { "data": "appr3"},
                    { "data": "appr4"},
                    { "data": "appr5"}
                ],
                "order": [[1, 'asc']]
            } );

and here is an example of an array I'm returning from the database

{
    "data": [
        {
            "empNum": "1",
            "empName": "BAKER, MARK E. ",
            "unitRate": 0,
            "salary": 3282.84,
            "hourly": 0,
            "appFlag": " ",
            "app1": "K002 1 ",
            "app2": " ",
            "app3": " ",
            "app4": " ",
            "app5": " "
        }

I don't know what I'm doing wrong or how to fix this. I've been searching and trying for about 6 hours now. Please help