Hi,
I have the same problem.
I tried the first solution to modify the appsetting ChartImageHanbler to:
<add key="ChartImageHandler" value="storage=file;timeout=20;dir=c:\TempImageFiles\;" />
With this solution I still get the error on PDF and now the charts are not displayed on the page. (I can see image files added to the c:\TempImageFiles directory so the security on the folder is ok)
I tried the second solution to change the location path project/ReportPdf.aspx to ~/project/ReportPdf.aspx and I still get the error Could not render the url. Could not get image from url.The URL is not accessible. Status code 0x191.The requested resource requires user authentication.