Index: lib/pathname.rb
===================================================================
--- lib/pathname.rb	(revision 23091)
+++ lib/pathname.rb	(working copy)
@@ -197,6 +197,12 @@
     # to_path is implemented so Pathname objects are usable with File.open, etc.
     TO_PATH = :to_path
   end
+
+	if RUBY_PLATFORM =~ /mswin|mingw/
+		COMPARISON = :casecmp
+	else
+		COMPARISON = :eql?
+	end
   # :startdoc:
 
   #
@@ -786,12 +792,12 @@
       base_prefix, basename = r
       base_names.unshift basename if basename != '.'
     end
-    if dest_prefix != base_prefix
+    if not (dest_prefix.send(COMPARISON, base_prefix))
       raise ArgumentError, "different prefix: #{dest_prefix.inspect} and #{base_directory.inspect}"
     end
     while !dest_names.empty? &&
           !base_names.empty? &&
-          dest_names.first == base_names.first
+          dest_names.first.send(COMPARISON, base_names.first)
       dest_names.shift
       base_names.shift
     end