http://developers.de/blogs/damir_dobric/archive/2011/09/03/task-schedule-service-exception-on-begindeletetask.aspxWhen working with Task Schedule Service you might get following exception when invoking BeginDeletTask: ArgumentException: Value Cannot be null. This exception is thrown by executing of following code: protected void Button2_Click( object sender, EventArgsenCommunityServer 2008 SP1 (Build: 30619.63)