ghc-6.8.* doesn't yet support QuasiQuotes.

BUT, there is a patched ghc-6.8.3 that *does*
support QuasiQuotes at:

http://code.haskell.org/~morrow/quasiquotes/ghc-6.8.3_QQ-0.1.tar.bz2

NOTE:
  ghc-6.8.3_QQ-0.1.tar.bz2 *already*
  has the extralibs included.

If you are unwilling/unable to use ghc-6.9, then building
ghc-6.8.3_QQ-0.1 is the only option.