UI automation for silverlight

Question

Hi All,
I tried enabling UI automation in silverlight by using IInvokeProvider.But when I build my application I get teh following error
The type 'System.Windows.Automation.Provider.IInvokeProvider' exists in both 'c:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0\UIAutomationProvider.dll' and 'c:\Program Files\Microsoft SDKs\Silverlight\v2.0\Reference Assemblies\System.Windows.dll'   

Can anyone help me resolve the error?

Thanks.

Regards,
Seena