For the past three years we have focused our efforts towards the new RadChartView
. It resolves many of the limitations that the old chart had. I suggest you upgrade to the latest version of our control and completely remove the Charting.dll reference and use the new Chart.dll with the new chart view.
I created a small project with a simple chart and an export button. The chart gets exported correctly on the click of the button. Can you modify the project to reproduce the exception and send it back to us for investigation? Also can share with us how did you encounter this problem? You are using assemblies from 2011, did you get the exception just now after updating your application or did you just start using our controls?
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.