diff --git a/app/controllers/admin_controller.rb b/app/controllers/admin_controller.rb
index 5aecd5f6d..dd3e91236 100644
--- a/app/controllers/admin_controller.rb
+++ b/app/controllers/admin_controller.rb
@@ -79,7 +79,7 @@ class AdminController < ApplicationController
           User.find(:first,
                     :conditions => ["login=? and hashed_password=?", 'admin', User.hash_password('admin')]).nil?],
       [:text_file_repository_writable, File.writable?(Attachment.storage_path)],
-      [:text_plugin_assets_writable,   File.writable?(Engines.public_directory)],
+      [:text_plugin_assets_writable,   File.writable?(Redmine::Plugin.public_directory)],
       [:text_rmagick_available,        Object.const_defined?(:Magick)]
     ]
   end
diff --git a/lib/redmine/plugin.rb b/lib/redmine/plugin.rb
index 2c77cf097..5c13e3d1f 100644
--- a/lib/redmine/plugin.rb
+++ b/lib/redmine/plugin.rb
@@ -43,6 +43,9 @@ module Redmine #:nodoc:
   #
   # When rendered, the plugin settings value is available as the local variable +settings+
   class Plugin
+    cattr_accessor :public_directory
+    self.public_directory = File.join(Rails.root, 'public', 'plugin_assets')
+
     @registered_plugins = {}
     class << self
       attr_reader :registered_plugins