diff --git a/pyreadline/console/console.py b/pyreadline/console/console.py
index 2204003..9487b88 100644
--- a/pyreadline/console/console.py
+++ b/pyreadline/console/console.py
@@ -30,6 +30,9 @@ try:
 except ImportError:
     raise ImportError(u"You need ctypes to run this code")
 
+if sys.version_info < (2, 6):
+    bytes = str
+
 def nolog(string):
     pass
     
@@ -690,7 +693,7 @@ def hook_wrapper_23(stdin, stdout, prompt):
         # call the Python hook
         res = ensure_str(readline_hook(prompt))
         # make sure it returned the right sort of thing
-        if res and not isinstance(res, str):
+        if res and not isinstance(res, bytes):
             raise TypeError, u'readline must return a string.'
     except KeyboardInterrupt:
         # GNU readline returns 0 on keyboard interrupt
@@ -714,7 +717,7 @@ def hook_wrapper(prompt):
         # call the Python hook
         res = ensure_str(readline_hook(prompt))
         # make sure it returned the right sort of thing
-        if res and not isinstance(res, str):
+        if res and not isinstance(res, bytes):
             raise TypeError, u'readline must return a string.'
     except KeyboardInterrupt:
         # GNU readline returns 0 on keyboard interrupt
@@ -738,7 +741,7 @@ def install_readline(hook):
     readline_hook = hook
     # get the address of PyOS_ReadlineFunctionPointer so we can update it
     PyOS_RFP = c_int.from_address(Console.GetProcAddress(sys.dllhandle,
-                                            "PyOS_ReadlineFunctionPointer"))
+                           "PyOS_ReadlineFunctionPointer".encode('ascii')))
     # save a reference to the generated C-callable so it doesn't go away
     if sys.version < '2.3':
         readline_ref = HOOKFUNC22(hook_wrapper)
diff --git a/pyreadline/modes/basemode.py b/pyreadline/modes/basemode.py
index df1147d..35e2e79 100644
--- a/pyreadline/modes/basemode.py
+++ b/pyreadline/modes/basemode.py
@@ -195,7 +195,7 @@ class BaseMode(object):
             i = 0
             while 1:
                 try:
-                    r = ensure_unicode(self.completer(text, i))
+                    r = self.completer(ensure_unicode(text), i)
                 except IndexError:
                     break
                 i += 1
@@ -215,7 +215,7 @@ class BaseMode(object):
                     break
             text = ensure_str(u''.join(buf[self.begidx:self.endidx]))
             log(u'file complete text="%s"' % ensure_unicode(text))
-            completions = map(ensure_unicode, glob.glob(os.path.expanduser(text) + '*'))
+            completions = map(ensure_unicode, glob.glob(os.path.expanduser(text) + '*'.encode('ascii')))
             if self.mark_directories == u'on':
                 mc = []
                 for f in completions:
diff --git a/pyreadline/unicode_helper.py b/pyreadline/unicode_helper.py
index bf171ab..7fffd9f 100644
--- a/pyreadline/unicode_helper.py
+++ b/pyreadline/unicode_helper.py
@@ -17,9 +17,12 @@ except AttributeError:
 if pyreadline_codepage is None:  
     pyreadline_codepage = u"ascii"
 
+if sys.version_info < (2, 6):
+    bytes = str
+
 def ensure_unicode(text):
     u"""helper to ensure that text passed to WriteConsoleW is unicode"""
-    if isinstance(text, str):
+    if isinstance(text, bytes):
         try:
             return text.decode(pyreadline_codepage, u"replace")
         except (LookupError, TypeError):