diff --git a/hoodle-core.cabal b/hoodle-core.cabal
--- a/hoodle-core.cabal
+++ b/hoodle-core.cabal
@@ -1,5 +1,5 @@
 Name:		hoodle-core
-Version:	0.9.0
+Version:	0.9.0.0
 Synopsis:	Core library for hoodle
 Description: 	Hoodle is a pen notetaking program written in haskell. 
                 hoodle-core is the core library written in haskell and 
@@ -42,7 +42,7 @@
                    pango == 0.12.*,
                    gd >= 3000.7,               
                    attoparsec == 0.10.*,
-                   coroutine-object >= 0.2, 
+                   coroutine-object >= 0.2.0, 
                    transformers == 0.3.*,
                    transformers-free == 1.0.*,
                    hoodle-types >= 0.1.1,
@@ -54,7 +54,7 @@
                    template-haskell == 2.*,
                    bytestring >= 0.9, 
                    base64-bytestring >= 0.1,
-                   either >= 3, 
+                   either >= 3.1, 
                    errors >= 1.3, 
                    lens >= 2.5,
                    process >= 1.1, 
diff --git a/src/Hoodle/Coroutine/File.hs b/src/Hoodle/Coroutine/File.hs
--- a/src/Hoodle/Coroutine/File.hs
+++ b/src/Hoodle/Coroutine/File.hs
@@ -328,10 +328,13 @@
 fileAnnotatePDF = 
     fileChooser FileChooserActionOpen Nothing >>= maybe (return ()) action 
   where 
+    warning = do 
+      okMessageBox "cannot load the pdf file. Check your hoodle compiled with poppler library"
+      invalidateAll 
     action filename = do  
       xstate <- get 
       mhdl <- liftIO $ makeNewHoodleWithPDF filename 
-      flip (maybe (return ())) mhdl $ \hdl -> do 
+      flip (maybe warning) mhdl $ \hdl -> do 
         xstateNew <- return . set currFileName Nothing 
                      =<< (liftIO $ constructNewHoodleStateFromHoodle hdl xstate)
         commit xstateNew 
diff --git a/src/Hoodle/ModelAction/File.hs b/src/Hoodle/ModelAction/File.hs
--- a/src/Hoodle/ModelAction/File.hs
+++ b/src/Hoodle/ModelAction/File.hs
@@ -114,7 +114,7 @@
               $ emptyHoodle
       return (Just hdl)
 #else
-  error "makeNewHoodleWithPDF should not be used without poppler lib"
+  return Nothing
 #endif
       
 -- | 
diff --git a/src/Hoodle/Type/Coroutine.hs b/src/Hoodle/Type/Coroutine.hs
--- a/src/Hoodle/Type/Coroutine.hs
+++ b/src/Hoodle/Type/Coroutine.hs
@@ -47,9 +47,11 @@
 doEvent :: (Monad m) => MyEvent -> CObjT MainOp m () 
 doEvent ev = request (Arg DoEvent ev) >> return ()
 
+{-
 instance (Monad m) => MonadState HoodleState (EStT HoodleState m) where
   get = lift get
   put = lift . put 
+-}
 
 -- |
 type MainCoroutine = MainObjB