Hi Ketil Particularly to Haskore rather than package importing or Cabal in general, AbsPitch is not defined in "Haskore" i.e. Henning Thielemann's extended Haskore. AbsPitch in Paul Hudak's Haskore (i.e. "haskore-vintage"), it is a synonym for Int, I believe the replacement is Henning's Haskore is Absolute. From what I can gather, the original poster is using Haskore from Hackage (so they have Henning's version) but is trying to work with an old library HasChorus (installed from a source tar ball that is not on Hackage). HasChorus doesn't have a cabal file to distinguish dependencies, but it is written for Paul Hudak's original Haskore - i.e. "haskore-vintage". The docs on Hackage show that Henning's Haskore doesn't export AbsPitch: http://hackage.haskell.org/packages/archive/haskore/0.1.0.4/doc/html/doc-ind... http://hackage.haskell.org/packages/archive/haskore-vintage/0.1/doc/html/doc... Best wishes Stephen