Hello there! This error is usually an issue with the software configuration. More then likely xcaliber change the way the application accesses files but no worries we can fix it either by following the steps below or having me securely connect to you and perform the steps outlined below. Your choice of course :)
1. If the application crashes, Force Quit out of QuarkXPress.
2. On the Finder level, go to the Hard Drive > Applications > QuarkXPress folder.
3. Inside the QuarkXPress folder, create a new folder by going to File > New Folder
4. Label the new folder Preferences (use an upper case P - It is important that Preferences be spelled correctly).
5. Launch QuarkXPress from the QuarkXPress folder.