System.ArgumentNullException: Value cannot be null. (Parameter 'source')
   at System.Linq.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument)
   at System.Linq.Enumerable.Where[TSource](IEnumerable`1 source, Func`2 predicate)
   at MVC.Extensions.PageCache.ProgramPageCacheExtension.FilterByCatalogId(List`1 value, String catalogNumber) in E:\dev\www.nwtc.edu.git\www.nwtc.edu\Web\mvc\Extensions\PageCache\ProgramPageCacheExtension.cs:line 39
   at MVC.Controllers.CourseCatalogController.GetRelatedPrograms(String catalogId) in E:\dev\www.nwtc.edu.git\www.nwtc.edu\Web\mvc\Controllers\CourseCatalogController.cs:line 373
   at MVC.Controllers.CourseCatalogController.Detail(String courseNumber, Int32 page, String location, String deliveryMode, String term) in E:\dev\www.nwtc.edu.git\www.nwtc.edu\Web\mvc\Controllers\CourseCatalogController.cs:line 106