In order to get the RadChart charting controls to work correctly in DotNetNuke you must first take into account that DNN rewrites all URLs to what are called ‘Pretty URLs’. Because of this the RadChart has a hard time locating the URL of the HttpHandler which creates the chart images.
To fix this you need to help the RadChart instance out by telling it where the HttpHandler URL is. This can be done by setting the HttpHandler URL through the RadChart’s HttpHandlerUrl property in the Page Load event of your DNN module control as shown below.
myRadChartInstance.HttpHandlerUrl = ResolveUrl("ChartImage.axd") ;