Diagnosis
An item has been selected for deletion in the 'block' mode which wasnot created when the action was carried out.

System Response
The system does not allow deletion.

Procedure
In the 'block' mode, you can only delete those items which have justbeen created. If you want to delete items which have been created priorto this, you have to select 'Disposition' --> 'Unblock' --> 'Item'.