Silverlight Error 0x17E0

Error 0x17E0. Debugging resource strings are unavailable. See http://go.microsoft.com/fwlink/?linkid=106663&Version=4.0.60129.0&File=mscorrc.dll&Key=0x17E0

Does anyone know what this error is? I get it when trying to Print in a loop.

 at RealForms.ViewModel.FormNewViewModel.<Print>d__48.MoveNext()     at 
    RealForms.ViewModel.FormNewViewModel.Print(Object parameter)     at 
    RealForms.ViewModel.FormNewViewModel.<.ctor>b开发者_开发问答__6(Object param)     at 
    GalaSoft.MvvmLight.Command.RelayCommand`1.Execute(Object parameter)     at 
    System.Windows.Controls.Primitives.ButtonBase.ExecuteCommand()     at 
    System.Windows.Controls.Primitives.ButtonBase.OnClick()     at 
    System.Windows.Controls.Button.OnClick()     at 
    System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)     
    at System.Windows.Controls.Control.OnMouseLeftButtonUp(Control ctrl, EventArgs e)     at 
    MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 
    argsTypeIndex, Int32 actualArgsTypeIndex, String eventName)

From my experience, that error indicates an InvalidCastException.