While working with Chart control in .net 4.0. I found the below issue.

A chart element with the name 'Default' could not be found in the 'ChartAreaCollection'.

Reason for the issue: It indicates that, the element default is not initilized as ChartAreaCollection.

To resolve this problem, we need to create it.

chartl.ChartAreaCollection.Add("Default");

The above line will resolve the problem.

Cheers,
Venkatesan Prabu .J
Head, www.kaashivinfotech.com