diff --git a/ChristmasTree.cabal b/ChristmasTree.cabal
--- a/ChristmasTree.cabal
+++ b/ChristmasTree.cabal
@@ -1,7 +1,7 @@
-cabal-version:      >=1.2
+cabal-version:      >=1.2.3
 build-type:         Simple
 name:               ChristmasTree
-version:            0.1
+version:            0.1.1
 license:            LGPL
 license-file:       COPYRIGHT
 maintainer:         Marcos Viera <mviera@fing.edu.uy>
@@ -11,7 +11,7 @@
 category:           Parsing 
 stability:          Experimental
 copyright:          Universiteit Utrecht
-build-depends:      base, haskell98, template-haskell, containers,
+build-depends:      base >= 2 && < 4, haskell98, template-haskell, containers,
                     fgl>=5.4, TTTAS, uulib 
 exposed-modules:    Text.GRead, Text.GShow, 
                     Text.GRead.Derive, Text.GRead.Grammar
diff --git a/src/Text/GRead.hs b/src/Text/GRead.hs
--- a/src/Text/GRead.hs
+++ b/src/Text/GRead.hs
@@ -108,7 +108,7 @@
     show Close    = ")"
 
 instance UU.Symbol Token where
-  deleteCost _ = 5
+  deleteCost _ = 5#
 
 
 -- PARSE ----------------------------------------------------------------------