Known Quark XPress/Panther Issue
Users of Quark XPress may experience trouble after upgrading to Apple's OS X Version 10.3 (Codename: Panther). The operating system upgrade apparently breaks the activation code causing an error message on startup, and disabling many of the most important features of XPress.

Until a patch or fix is developed Quark recommends this workaround.

• Locate the Quark folder from the Library/Preferences folder (I found one in the 10.2 System as well as one in the fresh Panther System) and drag to trash

• Locate the QuarkXPress Component installer in the 'For System' folder of the 'Quark XPress 6.0' folder and run it

• Launch the XPress application and you'll be prompted to Activate the application -- choose Over The Internet

NOTE: You may be required to get a new copy of your activation code from Quark in order to finish the activation. Be prepared for a lengthy process of e-mail and phone calls.

Quark has more information at its site here.