Why is --gen-script creating failing scripts?

I've been using the recent cabal from ghc-6.7.20070814 register.sh [...] haddock-html: /pr/store/5wivrfz8pmc7hpwqgxgz44i4ihf1ka09-ghc67_filepath-1.0/nix-support/share/filepath-1.0/doc/html/filepath' | /pr/store/khvbwb3whj1c15pg7jrh7w4v2vndr8i7-ghc-6.7.20070814/bin/ghc-pkg update dist/installed-pkg-config - marc@localhost /tmp/nix-10368-0/filepath-1.0 $ ghc-pkg list /pr/store/khvbwb3whj1c15pg7jrh7w4v2vndr8i7-ghc-6.7.20070814/lib/ghc-6.7.20070814/package.conf: Cabal-1.1.7, [...] Please use either echo and add - or pass the pkg-conf dist/installed-pkg-config .. or did I mess something up? If you like I can start debugging the issue and read the source.. But propably you know what has been changed ? Marc