Project won't load after adding reference to Telerik.Windows.Controls.Navigation

[Paul]

Hi

I have a silverlight 5 application using Prism 4 + MEF using Telerik version 2011.3 1220.  In one of the modules if I add a Telerik control that adds the Telerik.Windows.Control.Navigation the application will not load with the following:

Message:

Failed to load type for module HomeScreenModule.

If this error occurred when using MEF in a Silverlight application, please ensure that the CopyLocal property of the reference to the MefExtensions assembly is set to true in the main application/shell and false in all other assemblies.

Error was: The package downloaded successfully but an error occurred while reading the contents of the package. See the inner exception for more details..

Copy local is set to false in the modules and set to true in the Shell app.

Stacktrace:
   at Microsoft.Practices.Prism.Modularity.ModuleManager.HandleModuleTypeLoadingError(ModuleInfo moduleInfo, Exception exception)
   at Microsoft.Practices.Prism.Modularity.ModuleManager.IModuleTypeLoader_LoadModuleCompleted(Object sender, LoadModuleCompletedEventArgs e)
   at Microsoft.Practices.Prism.MefExtensions.Modularity.MefXapModuleTypeLoader.RaiseLoadModuleCompleted(LoadModuleCompletedEventArgs e)
   at Microsoft.Practices.Prism.MefExtensions.Modularity.MefXapModuleTypeLoader.RaiseLoadModuleCompleted(ModuleInfo moduleInfo, Exception error)
   at Microsoft.Practices.Prism.MefExtensions.Modularity.MefXapModuleTypeLoader.HandleDownloadCompleted(DeploymentCatalog deploymentCatalog, AsyncCompletedEventArgs e)
   at Microsoft.Practices.Prism.MefExtensions.Modularity.MefXapModuleTypeLoader.DeploymentCatalog_DownloadCompleted(Object sender, AsyncCompletedEventArgs e)
   at System.ComponentModel.Composition.Hosting.DeploymentCatalog.OnDownloadCompleted(AsyncCompletedEventArgs e)
   at System.ComponentModel.Composition.Hosting.DeploymentCatalog.HandleOpenReadCompleted(Object sender, OpenReadCompletedEventArgs e)
   at System.Net.WebClient.OnOpenReadCompleted(OpenReadCompletedEventArgs e)
   at System.Net.WebClient.OpenReadOperationCompleted(Object arg)

If I remove the control and remove the reference to Telerik.Windows.Controls.Navigation everything works fine.  I have the radDatePicker control in this module and that doesn't cause me any problems.

Does anyone know why this is happening?
Thanks
Paul

[Paul]

Hi

Found the answer here: http://www.telerik.com/community/forums/silverlight/general-discussions/telerik-libs-prism-app.aspx.
Only happens with some Telerik assembly's
Thanks
Paul