Your Poser and Vista problem in not uncommon judging by the number ot posts addressing this issue in the forum.  I am betting you installed your Poser App in 'Program Files' which is a very big No-No where Vista is concerned.  The OS is very finicky about content changes in that folder and will not allow you to make physical changes.  The recommended solution is to install Poser in it's own folder on your main drive, i.e., C:/Poser.  This will remedy any further headaches.