IVsTaskList must be installed for this feature to work

Hi

I am trying to add custom errors to errors task list on visual studio 2008 through an add-in. It works fine on visual studio 2008 professional edition but not on team system edition. Any idea?

errors that we see:

Exception in method: a [Inner Exception:System.InvalidOperationException: The service 'Microsoft.VisualStudio.Shell.Interop.IVsTaskList' must be installed for this feature to work.  Ensure that this service is available.

   at Microsoft.VisualStudio.Shell.TaskProvider.get_VsTaskList()

   at Microsoft.VisualStudio.Shell.ErrorListProvider.get_VsTaskList()

   at Microsoft.VisualStudio.Shell.TaskProvider.Refresh()

   at Microsoft.VisualStudio.Shell.TaskProvider.TaskCollection.Add(Task task)

   at a.a(String A_0, String A_1, TaskErrorCategory A_2, Int32 A_3, Int32 A_4) ]

Regards, Sujasree