diff --git a/Math/Combinat/Permutations.hs b/Math/Combinat/Permutations.hs
--- a/Math/Combinat/Permutations.hs
+++ b/Math/Combinat/Permutations.hs
@@ -347,7 +347,7 @@
     ar <- newArray_ (1,n) 
     forM_ [1..n] $ \i -> writeArray ar i i
     rnd' <- worker n (if isSattolo then n-1 else n) rnd ar 
-    perm <- unsafeFreeze ar
+    perm <- Data.Array.Unsafe.unsafeFreeze ar
     return (Permutation perm, rnd')
   worker :: RandomGen g => Int -> Int -> g -> STUArray s Int Int -> ST s g 
   worker n m rnd ar = 
diff --git a/Math/Combinat/Trees/Binary.hs b/Math/Combinat/Trees/Binary.hs
--- a/Math/Combinat/Trees/Binary.hs
+++ b/Math/Combinat/Trees/Binary.hs
@@ -335,7 +335,7 @@
   res = runST $ do
     ar <- newArray (0,2*n0) 0
     rnd' <- worker rnd 1 ar
-    links <- unsafeFreeze ar
+    links <- Data.Array.Unsafe.unsafeFreeze ar
     return (toTree links, rnd')
   toTree links = f (links!0) where
     f i = if odd i 
diff --git a/combinat.cabal b/combinat.cabal
--- a/combinat.cabal
+++ b/combinat.cabal
@@ -1,5 +1,5 @@
 Name:                combinat
-Version:             0.2.6.0
+Version:             0.2.6.1
 Synopsis:            Generation of various combinatorial objects.
 Description:         A collection of functions to generate (and if there is 
                      a formula, count) combinatorial objects like partitions,