Charting Control Error - Invalid temp directory in chart handler configuration 

You may receive the following error when using the Microsoft Charting Controls for ASP.NET:

Invalid temp directory in chart handler configuration

To resolve this issue, set a temporary directory within your site like the following:

<appSettings>
<add key="ChartImageHandler" value="storage=file;timeout=20;Url=~/chartTmpImages/;"/>
</appSettings>

Ensure that the directory has been created first from FTP.