This sounds like the Vista and Windows 7 UAC issue which has been covered extensively here in the forum.  I am assuming that Poser, and Clothes Converter, has been placed within the Program Files Folder of your OS.  If this is the case, and if you have not given proper administrative authorization, Vista and Windows 7 will prevent any file changes to occur within the Program Files Folder.  Best advice to avoid this problem is to put the programs into their own folders on the root drive.  If this doesn't resolve the problem, contact DAZ for either a refund or how to contact the vendor.