title: Highstock giving error 15
body: <p>I added two time series in highstock , but after running the sample , I get this error <strong><em>: Highcharts error #15</em></strong> in console also browser does not show properly.I checked for this error but time series data is in ascending order only, so could not make out why this error coming up ?</p>
  
  <pre><code>$('#chartdiv').highcharts('StockChart', {
      rangeSelector: {
          selected: 2
      },
      legend: {
          enabled: true
      },
      credits: {
          enabled: false
      },
      chart: {
          zoomType: 'x'
      },
      title: {
          text: 'test highchart'
      },
      series: seriesOptions
  });
  </code></pre>
  
  <p><a href="http://jsfiddle.net/BHUPENDRA1011/0tfkfh2v/3/" rel="nofollow">Here</a> is the fiddle for above issue.</p>