diff --git a/UData.hs b/UData.hs
index 983df31..6706bcc 100644
--- a/UData.hs
+++ b/UData.hs
@@ -45,7 +45,7 @@ applyBVal :: BValue -> BValue -> BResult
 applyBVal (BFuncVal b) (BNumVal v) = applyBFunc b v
 applyBVal (BFuncVal b) _ = BException ("cannot apply built-in function "++(showBFunc b)++" on non-numeric value")
 applyBVal (BIntList args) (BNumVal (BInt v)) = BClean (BIntList (v:args))
-applyBVal (BIntList args) _ = BException "cannot append non-integer number in IntList"
+applyBVal (BIntList args) _ = BException "cannot append non-integer number to IntList"
 applyBVal _ _ = BException "cannot use numeric value as function"
 
 applyBFunc :: BFunc -> BNum -> BResult
diff --git a/UEnvironment.hs b/UEnvironment.hs
index 29b9a27..6edd8c2 100644
--- a/UEnvironment.hs
+++ b/UEnvironment.hs
@@ -86,7 +86,7 @@ instance UEnv URealWorldEnv where
 		else if (any (not.isValidCharInt) filename) then
 			return ((-3),initfiles)
 		else
-			(openFile (map chr filename) (efOpenModes!!mode) >>=
+			(openBinaryFile (map chr filename) (efOpenModes!!mode) >>=
 				(\handle -> ( let (fno,files1) = flAddHandle handle initfiles in
 					return (fno,files1)
 				)))
diff --git a/test.u b/test.u
index c14bd15..aed3966 100644
--- a/test.u
+++ b/test.u
@@ -1,6 +1,12 @@
 (import* str)
 (import* io)
 (run
+	(fin (open "2.bin" 0))
+	(c (getCharF fin))
+	(_ (putStrLn (itoa c)))
+	;(fout (open "2.bin" 1))
+	;(_ (putCharF fout 255))
+	;(_ (close fout))
 	;(line readLine)
 	;(_ (putStrLn line))
 	;(r (system "ls -l"))