i have downloaded revit archi 2009 and all four training files. but i am unable to unzip them as it says its already exists and cannot replace them. i think by default there are two folders in RAC 2009- common and metric- and i have saved the zip files on RAC 2009 folder. how do i get to them to unzip as i am missing express workshop training files when i started to do the tutorials. i have files upto worksets but nothing after that.