I got this same thing and I don't know what Microsoft did
to screw this awesome application up!
What I found was that if I opened Northwind Traders,
everything seemed to work fine, but when I tried to open a
DB I started to build before loading SP8, it wouldn't
work! So I started to build it new AFTER having loaded
SP8, and it seems to work fine. HOWEVER... it only works
fine when I log in as administrator and not a user. When
I log in as a user, again, I get that message and it won't
work. I even set Macro security to Low and it still goofs
up! Sorry, I don't have the answers yet!