Databound Checkboxes problem

Hello,

I am trying to databind some data to the RadTreeView control and setting the CheckedMember to a boolean property. Every time I check a checkbox in the treeview an exception is raised:

"An unhandled exception of type 'System.ArgumentException' occurred in System.dll
Additional information:  'Telerik.WinControls.Enumerations.ToggleState' can't be cast to 'System.Boolean'.

I am using the 2014.3 Version of the RadTreeView control .

 I have tried th example that is in the documentation, and the same happens.

Does anybody had this problem?

Thanks,

Lorenzo.