'Cannot call method 'toString' of undefined' in Kendo.all.min.js:6396

[Sander]

Hi all,

I'm getting a method 'toString' error when i render some line and bar/column charts.
Below is an example of one of the charts.

function widget1() {

        $("#widget1").kendoChart({

            theme: $(document).data("kendoSkin") || "default",

            title: {

                text: "Classificaties"

            },

            legend: {

                position: "left"

            },

            chartArea: {

                background: ""

            },

            seriesDefaults: {

                type: "column", stack: false

            },

            series: [{name: "1 Incident",

            data: [1,1,4,9,2],

                        color: "#DB3030"},

                        {name: "2 Probleem",

            data: [,,,,],

                        color: "#8A2424"},

                        {name: "3 Wijzigingsverzoek",

            data: [,,,1,3],

                        color: "#663399"},

                        {name: "3a Algemene wijziging",

            data: [,,,,],

                        color: "#993399"},

                        {name: "3b Standaard wijziging",

            data: [,,,,],

                        color: "#9966CC"},

                        {name: "3c Projectwijziging",

            data: [,,,,],

                        color: "#CC66CC"},

                        {name: "4 Vraag",

            data: [,,,,],

                        color: "#34B8C7"},

                        {name: "5 Beheer",

            data: [,,,,],

                        color: "#346CC7"},

                        ],

            valueAxis: {

                labels: {

                    format: "{0}"

                }

            },

            categoryAxis: {

                categories: [48,49,50,51,52]

            },

            tooltip: {

                visible: true,

                template: "${value}"

            },

            seriesClick: widget1Click,

            transitions: false

        });

    }