Hmm,
Now when I tried to run Leksah, I get not only some broken packages (which I can avoid for my current project), but:

<command line>: cannot satisfy -package-id base-4.5.1.0-7c83b96f47f23db63c42a56351dcb917:
    base-4.5.1.0-7c83b96f47f23db63c42a56351dcb917 is unusable due to missing or recursive dependencies:

      integer-gmp-0.4.0.0-c15e185526893c3119f809251aac8c5b
  (use -v for more information)

So I tried to install base, then re-install it, but both fail;
Any hints?

From this email and some of the previous emails it seems that your package DB is in a pretty bad state, most likely from using --force-reinstalls. When Cabal warns you that this will break stuff it actually means it. :) My suggestion is that you

rm -rf ~/.ghc/x86_64-linux-7.6.1 # or equivalent on your system.

Then reinstall all the packages you want by listing them all at once

cabal install pkg1 pkg2 pk3

By listing them all together cabal-install tries to come up with an install plan that is globally consistent for all of them.

-- Johan