Permanantly unresolved cross references?
I have some files in a book that ALWAYS have unresolved cross references, and I don't understand why.
When I open the files, I get this message:

This happens for several files in the book. Always the same ones.
So I fix the unresolved cross references using the Find/Cross References-Unresolved tool and repairing them on the Cross References menu. After the "Find" yields no more unresolved cross references, I save all of the files. Then I update the book.
But despite saving ALL of these files, once they are closed and opened again, they once again have the SAME unresolved cross references, even though NOTHING has changed since I repaired the unresolved cross references and saved the files.
How is this happening and how do I fix it, permanantly?
Thank you.
