FM 11: Chapter numbering is not working. I get blanks!

I am having chapter numbering issues.I am using FM 11. I have h1u set as A:Unit <$chapnum>. with Autonumber format checked. I have tried numbering each individual unit and selecting Update Book. However, the numbers are all reset to blanks. I have tried setting the numbering from the book and the same results. Blanks! How do I fix this?