Thank you for writing.
In Q2 2012 we have introduced a new charting mechanism which will replace the previous one. Currently, both are shipped with our suite and we will not remove/obsolete the old one until the new mechanism covers all features.
The warning you get is because there are similar namespaces in the two chart assemblies. There are two things you can do to resolve this:
1. You can either use the full namespace of the class or use the include/using directive with the correct namespace.
2. You can add only a reference to the assembly of the chart mechanism you are using and not include or remove the other one.
The assemblies are:
old mechanism - Telerik.WinControls.RadChart
new mechanism - Telerik.WinControls.ChartView
I hope this will be useful. Should you have further questions, I would be glad to help.
the Telerik team