It has only been a week since the last Vista Transformation Pack was released but some changes were in order since Microsoft made Vista Pre-RC1 available to the public. Vista Transformation Pack 5.5 has added the cursors, icons, tray icons, and background from Vista Pre-RC1 along with several bug fixes.
That means if you were having problems installing or using the last pack it will hopefully work for you this time. Your other alternative, if you didn’t get Vista Pre-RC1, would be to wait around a week to download Vista RC1 and then you’ll have the real thing…bugs and all. ;)