The folks at IBM introduced a new view, ($PeopleGroupsFlatExt) in the mail file.
It is not in the 1.7b template, so, if you sync your local address book to your mail file, create a new mail in DWA, hit the "To" button, and select "contacts" you will get an error.
I added the view from a 6.5.5 iNotes6.ntf and the error goes away.
Did we really need another view in there IBM?
Anyway, it would probably be good to include this view now.
Thanks,
-Joe