diff --git a/Text/NKJP/Morphosyntax.hs b/Text/NKJP/Morphosyntax.hs
--- a/Text/NKJP/Morphosyntax.hs
+++ b/Text/NKJP/Morphosyntax.hs
@@ -87,7 +87,7 @@
 
 readTar :: FilePath -> IO [Tar.Entry]
 readTar tar
-    =  Tar.foldEntries (:) [] error
+    =  Tar.foldEntries (:) [] (error . show)
     .  Tar.read . GZip.decompress
    <$> BS.readFile tar
 
diff --git a/Text/NKJP/Named.hs b/Text/NKJP/Named.hs
--- a/Text/NKJP/Named.hs
+++ b/Text/NKJP/Named.hs
@@ -108,7 +108,7 @@
 
 readTar :: FilePath -> IO [Tar.Entry]
 readTar tar
-    =  Tar.foldEntries (:) [] error
+    =  Tar.foldEntries (:) [] (error . show)
     .  Tar.read . GZip.decompress
    <$> BS.readFile tar
 
diff --git a/nkjp.cabal b/nkjp.cabal
--- a/nkjp.cabal
+++ b/nkjp.cabal
@@ -1,5 +1,5 @@
 name:               nkjp
-version:            0.1.0
+version:            0.1.1
 synopsis:           Manipulating the National Corpus of Polish (NKJP)
 description:
     The library provides parsing and printing utilities for the
@@ -23,7 +23,7 @@
       , polysoup
       , bytestring
       , zlib
-      , tar
+      , tar >= 0.4 && < 0.5
       , filepath
       , data-named