Building cabal with cabal fails?

Hi, Using GHC 6.4.2, in prepration for some cabal hacking, I decided to download Cabal from darcs and install it. darcs get http://darcs.haskell.org/packages/Cabal --partial cd Cabal runhaskell Setup configure And I get the error: ./Distribution/Simple.hs:61:1: lexical error Should this work? If not, what should I be doing. Thanks Neil