Remove the contents of the Profiles folder from the following locations and then place them in a separate folder:
HDD/System/Library/Colorsync/Profiles (One needs to copy these profiles to some location and then delete them as they are the system ones)
Once you have removed the profiles, test to see if QuarkXPress 8 will launch. If it launches successfully, the problem is that one of the profiles is corrupted. Work through a binary search to determine which profile is causing the problem.
Under some circumstances QuarkXPress 8 will not even get to the point during launch that the splash screen displays. If you encounter this problem, you can address it by resetting your ColorSync profiles.