I am also having issues with showing date labels or tooltips on mutiple lines. I get Invalid XML Data as well. I have copied and pasted your code from your documentation and it does not work. I put the chart in Debug mode and get :ERROR: Invalid XML encountered. An attribute value is not properly terminated. Check the XML data that you've provided. If you've special characters in your XML (like %, &, ' or accented characters), please URL Encode them.
I have tried Bar2D, Column2D and Column3D all with the same results.
