This QuarkXPress diary generation message means that QuarkXPress cannot find a textbox that is marked for deletion (usually, either as the result of a macro, or as the result of a zap token). This is usually due to multiple layers of grouping that have previously deleted the current object as the side-effect of another deletion.
When you encounter this message, you should use the View Messages option at the end of diary generation to determine if the message can be ignored (ie. the output looks OK) or if there is a problem at the box identified by the message. In either case, you should simplify your grid by making sure that there are no groups grouped to other objects or groups.
If you encounter this message, please send us the script by technical support, so that we can analyze it.