CHM not displaying content, only TOC, Index, and Search (RH 11)

Good morning,

I have a project created in RH 7 which I just converted to RH 11.  Have not worked on this particular project before.  WebHelp was generated with no issus (so far), but when I tried to generate a CHM, I see the TOC, Index and Search panes but no topic content displays when a topic is selected.  Where should I be looking to find out what the problem is?  I have not worked on this particular project - was created by another writer and I'm just taking it on.

Thanks for any help.

Diane