The latest version (1.14) on hackage fails under ghc --version The Glorious Glasgow Haskell Compilation System, version 6.10.1 Curiously, I think I built it at work under windows yesterday but maybe I was using ghc 6.8. I can't check until Monday. FileNameUtils.lhs:81:35: Ambiguous type variable `b' in the constraint: `GHC.Exception.Exception b' arising from a use of `catch' at FileNameUtils.lhs:(81,35)-(89,60) Probable fix: add a type signature that fixes these type variable(s) FileNameUtils.lhs:98:44: Ambiguous type variable `e2' in the constraint: `GHC.Exception.Exception e2' arising from a use of `try' at FileNameUtils.lhs:98:44-57 Probable fix: add a type signature that fixes these type variable(s) FileNameUtils.lhs:118:35: Ambiguous type variable `e1' in the constraint: `GHC.Exception.Exception e1' arising from a use of `catch' at FileNameUtils.lhs:(118,35)-(119,104) Probable fix: add a type signature that fixes these type variable(s) FileNameUtils.lhs:122:35: Ambiguous type variable `e' in the constraint: `GHC.Exception.Exception e' arising from a use of `catch' at FileNameUtils.lhs:122:35-54 Probable fix: add a type signature that fixes these type variable(s)