Text in the FrameMaker TOC is not providing links to the content

Hi,

I have a book that contains 7 chapters, and only one chapter in the TOC has working links for the heading and sub headings. I have tried different ways to make the content in the remaining six chapters clickable, but nothing has worked. I have tried to insert cross references and hyperlinks but they haven't worked. I have tried to determine how the one chapter in the book is different from the rest WRT the TOC, but don't see any differences. 

I really don't know what else to try.  Any help or tips would be great.

Thank you.

Cheers,

Elizabeth