error_PPT automation

While running my PPT workflow the following error is thoughing…
RemoteException wrapping System.Runtime.InteropServices.COMException: Error HRESULT E_FAIL has been returned from a call to a COM component.
at BalaReva.EasyPowerPoint.Scope.Slides.SlideExtractor.Execute(CodeActivityContext context)
at System.Activities.CodeActivity.InternalExecute(ActivityInstance instance, ActivityExecutor executor, BookmarkManager bookmarkManager)
at System.Activities.ActivityInstance.Execute(ActivityExecutor executor, BookmarkManager bookmarkManager)
at System.Activities.Runtime.ActivityExecutor.ExecuteActivityWorkItem.ExecuteBody(ActivityExecutor executor, BookmarkManager bookmarkManager, Location resultLocation)

what could be the reason?? main.xaml file attached

Main.xaml (7.8 KB)