Invalid value for <path> attribute

Before actually plotting the graph, I needed to convert the dates with the following line:

for (i = 0; i < data.length; i++) {                data[i].Date = parseDate(data[i].Date);            }

This line can be seen in the following, final code:

var data;            var margin = { top: 20, right: 60, bottom: 30, left: 50 },                width = 1000 - margin.left - margin.right,                height = 300 - margin.top - margin.bottom;            function parseDateForViewing(d) {                return d3.time.format('%b %Y')(d3.time.format('%m/%d/%Y').parse(d));            }            function parseDate2(d) {                return d3.time.format('%c')(d3.time.format('%m/%d/%Y').parse(d));            }            var parseDate = d3.time.format("%m/%d/%Y").parse;            var x = d3.time.scale()                .range([0, width]);            var y = d3.scale.linear()                .range([height, 0]);            var xAxis = d3.svg.axis()                .scale(x)                .orient("bottom");            var yAxis = d3.svg.axis()                .scale(y)                .orient("left");            var line = d3.svg.line()                .x(function (d) { return x(d.Date); })                .y(function (d) { return y(d.NumberOfActive); });            var svg = d3.select("#svgsection").append("svg")                .attr("width", width + margin.left + margin.right)                .attr("height", height + margin.top + margin.bottom)                .append("g")                .attr("transform", "translate(" + margin.left + "," + margin.top + ")");            var d = thedata.d;            data = thedata.d;            var _len = d.length;            var post, i;            for (i = 0; i < data.length; i++) {                data[i].Date = parseDate(data[i].Date);            }            for (i = 0; i < data.length; i++) {                d = data[i];                x.domain(d3.extent(data, function (d) { return d.Date; }));                y.domain(d3.extent(data, function (d) { return d.NumberOfActive; }));                svg.append("g")                    .attr("class", "x axis")                    .attr("transform", "translate(0," + height + ")")                    .call(xAxis);                svg.append("g")                    .attr("class", "y axis")                    .call(yAxis)                    .append("text")                    .attr("transform", "rotate(-90)")                    .attr("y", 6)                    .attr("dy", ".71em")                    .style("text-anchor", "end")                    .text("Closed Loans");                svg.append("path")                    .datum(data)                    .attr("class", "line")                    .attr("d", line);                svg.append("text")                .attr("x", (width / 2))                .attr("y", 0 - (margin.top / 2) + 10)                .attr("text-anchor", "middle")                .style("font-size", "16px")                .text("Closed Loans by Month");

I faced the same problem with my code.I found that it is because if there is no value then this error will come.We have to make a check for the value we are using like : if(!value){ value=correct_value; }