There's no need to wire to the DataBound event of the Chart just to map the Series DataXColumn.
This can be done in Page_Load.
I've attached a sample that demonstrates it. Note that RadChart does not support DateTime values directly. DateTime values should be converted to their OLE Automation equivalents using the ToOADate()
the Telerik team
Q2’11 SP1 of RadControls for WinForms is available for download (see what's new); also available is the Q3'11 Roadmap for Telerik Windows Forms controls.