Haddock won't build on 6.8.1

I see this:

$ runhaskell ./Setup.lhs build
Preprocessing executables for haddock-0.8...
shift/reduce conflicts:  5
Building haddock-0.8...

src/Main.hs:49:7:
     Could not find module `System.Directory':
       it is a member of package directory-1.0.0.0, which is hidden

Any ideas?

Thanks,
Deborah