diff --git a/Text/ParserCombinators/Parsek/Position.hs b/Text/ParserCombinators/Parsek/Position.hs
--- a/Text/ParserCombinators/Parsek/Position.hs
+++ b/Text/ParserCombinators/Parsek/Position.hs
@@ -28,9 +28,10 @@
 import Text.ParserCombinators.Parsek hiding (parse,parseFromFile,Parser)
 import qualified Text.ParserCombinators.Parsek as P
 import Data.Bits
+import Control.Monad.Fail as Fail
 
 newtype Parser a = PP (P.Parser (Char, SourcePos) a)
-  deriving (Alternative, Applicative, Monad, Functor, MonadPlus)
+  deriving (Alternative, Applicative, Monad, Functor, MonadPlus, MonadFail)
 
 instance IsParser Parser where
   type SymbolOf Parser = Char
diff --git a/parsek.cabal b/parsek.cabal
--- a/parsek.cabal
+++ b/parsek.cabal
@@ -1,5 +1,5 @@
 name:           parsek
-version:        1.0.3.0
+version:        1.0.4.0
 category:       Parsing
 synopsis:       Parallel Parsing Processes
 description: Koen Claessen's PPP, Modified.