Word TOC not linked; all other links work

Hi everyone,
 
I'm supporting an offsite user who has Acrobat X and Word 2007 running on Windows 7. When she converts one of her Word documents to pdf the Table of Contents entries aren't linked, even though the other Tables (Table of Tables, Table of Figures) and all other hyperlinks created in Word do work.
 
In other documents we've tested the TOC is linked upon conversion.
 
And finally, some friends at another company have reported this same problem converting Word 2007 documents using Acrobat X.
 
Thanks in advance for any help...
 
Beej