Index: railties/lib/rails/plugin/loader.rb
===================================================================
--- railties/lib/rails/plugin/loader.rb	(revision 652)
+++ railties/lib/rails/plugin/loader.rb	(working copy)
@@ -44,9 +44,9 @@
       def add_plugin_load_paths
         plugins.each do |plugin|
           plugin.load_paths.each do |path|
-            $LOAD_PATH.insert(application_lib_index + 1, path)
-            Dependencies.load_paths      << path
-            Dependencies.load_once_paths << path
+            [$LOAD_PATH, Dependencies.load_paths, Dependencies.load_once_paths].each do |paths|
+              paths.insert(application_lib_index(paths) + 1, path)
+            end
           end
         end
         $LOAD_PATH.uniq!
@@ -96,9 +96,9 @@
           end        
         end
 
-        def application_lib_index
-          $LOAD_PATH.index(File.join(RAILS_ROOT, 'lib')) || 0
-        end      
+        def application_lib_index(paths = $LOAD_PATH)
+          paths.index(File.join(RAILS_ROOT, 'lib')) || 0
+        end
 
         def enabled?(plugin)
           !explicit_plugin_loading_order? || registered?(plugin)