XamlParseException Occured

I am getting the same error with Silverlight 5 and the latest version of the UI for Silverlight. Your link to the Public Issue Tracking Forum no longer works. My list box has draggable items, and if I comment out the draganddrop portion of the xaml I don't get the error.

System.Windows.Markup.XamlParseException occurred
  Message= [Line: 0 Position: 0]
  LineNumber=0
  LinePosition=0
  StackTrace:
       at MS.Internal.XcpImports.CheckHResult(UInt32 hr)
  InnerException: System.Windows.Markup.XamlParseException
       Message= [Line: 0 Position: 0]
       LineNumber=0
       LinePosition=0
       StackTrace:
            at MS.Internal.XcpImports.CheckHResult(UInt32 hr)
            at MS.Internal.XcpImports.SetValue(IManagedPeerBase obj, DependencyProperty property, DependencyObject doh)
            at MS.Internal.XcpImports.SetValue(IManagedPeerBase doh, DependencyProperty property, Object obj)
            at System.Windows.DependencyObject.SetObjectValueToCore(DependencyProperty dp, Object value)
            at System.Windows.DependencyObject.SetEffectiveValue(DependencyProperty property, EffectiveValueEntry& newEntry, Object newValue)
            at System.Windows.DependencyObject.UpdateEffectiveValue(DependencyProperty property, EffectiveValueEntry oldEntry, EffectiveValueEntry& newEntry, ValueOperation operation)
            at System.Windows.DependencyObject.SetValueInternal(DependencyProperty dp, Object value, Boolean allowReadOnlySet, Boolean isBindingInStyleSetter)
            at Telerik.Windows.Controls.ItemsControl.PrepareContentControl(Object item, ContentControl element)
            at Telerik.Windows.Controls.ItemsControl.PrepareContainerForItemOverride(DependencyObject element, Object item)
            at Telerik.Windows.Controls.Primitives.ListControl.PrepareContainerForItemOverride(DependencyObject element, Object item)
            at System.Windows.Controls.ItemsControl.MS.Internal.Controls.IGeneratorHost.PrepareItemContainer(DependencyObject container, Object item)
            at System.Windows.Controls.ItemContainerGenerator.System.Windows.Controls.Primitives.IItemContainerGenerator.PrepareItemContainer(DependencyObject container)
            at System.Windows.Controls.VirtualizingStackPanel.InsertContainer(Int32 childIndex, UIElement container, Boolean isRecycled)
            at System.Windows.Controls.VirtualizingStackPanel.AddContainerFromGenerator(Int32 childIndex, UIElement child, Boolean newlyRealized)
            at System.Windows.Controls.VirtualizingStackPanel.MeasureOverride(Size constraint)
            at System.Windows.FrameworkElement.MeasureOverride(IntPtr nativeTarget, Single inWidth, Single inHeight, Single& outWidth, Single& outHeight)
       InnerException: 

Nothing is on the stack that I can debug without debugging into .Net internals. I do not want to post the code publicly, can I email it to you?