You can resolve this problem by following these steps:
- Extract the files of the installer into a new folder on the desktop.
- Run the Setup.exe from the new folder.
When the downloaded installer is used to install QuarkXPress on a new machine, not all the installer files are decompressed correctly. The error message can occur if the Setup.exe is executed from the zipped folder. You need to decompress the downloaded file completely to a different folder in order for QuarkXPress to install all the components correctly.