When working with Microsoft Chart Control.
You sometime get error:
1)Error executing child request for ChartImg.axd
or
2)No http handler was found for request type 'POST' and Chart control
For error 2 you just need to add
<add path="ChartImg.axd" verb="GET,HEAD,POST" type="System.Web.UI.DataVisualization.Charting.ChartHttpHandler, System.Web.DataVisualization, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" validate="false" />
to the handler in your web.config
Solution to error 1:
It could also be a permission problem with the image not found error.
Set the "Allow modify" permissions on your image folder (per default it is "C:\TempImageFiles" for the account under which your website is running.
Another solution i found out is you will have to set your website to application pool to use "Classic Asp.net" - This is for IIS 7.0
Hope it helps