[Haskell-cafe] "could not create compact unwind"

I just did cabal install cabal-install on a Mac running Mac OS 10.6.8 and got the eventual response [44 of 44] Compiling Main ( Main.hs, dist/build/cabal/cabal-tmp/Main.o ) Linking dist/build/cabal/cabal ... ld: warning: could not create compact unwind for .LFB3: non-standard register 5 being saved in prolog Installing executable(s) in /home/cshome/o/ok/.cabal/bin I also had this problem today: m% cabal install quickcheck Resolving dependencies... cabal: dependencies conflict: ghc-6.12.3 requires pretty ==1.0.1.2 however pretty-1.0.1.2 was excluded because ghc-6.12.3 requires pretty ==1.0.1.1 What's the procedure for wiping everything out and starting again?