This message should almost never happen, unless your preferences file has been damaged.
However it is an easy problem to fix :
|1.||Go to the TOOLS menu and select the Preferences menu item. Alternatively, you can use the corresponnding button on the toolbar.|
|2.||Select the QuarkXPress button form the list of buttons at the left of the dialog which appears.|
|3.||Set the Quark Version to 4.x (unless you are still using QuarkXPress 3.3x).|
|4.||While you are at it, you should verify that the value for Rescan Delay is about 300 ms, and that the option Open QuarkXPress using the Windows shell is checked.|
When you are done, click on OK to save these changes.