Hmm, its possible that the disk is bad, which is uncommon but not impossible. If so, you should contact your retailer, where you purchased the disk, or else contact Westcott, who distributes PhotoKey Lite, at
800-886-1689 or firstname.lastname@example.org
Although FXhome developed PhotoKey Lite for Westcott, we don't directly distribute it ourselves. Westcott should be able to set you up with either a replacement disk or access to a download version of your software though.