ChartDirector is self contained and does not need DWrite.dll. So the lack of DWrite.dll will not affect ChartDirector.
From your description, I assume you are using the XYChart directly (as opposed to a FinanceChart). By "heading", I assume you are referring the legend keys. (So the lines are visible, but there is no text to label those lines.)
To show the legend keys, your code needs to specify the position to show the keys and how the key should be layout. Some examples are: