diff --git a/Gemfile.lock b/Gemfile.lock
index 596209f8..d45de989 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -7,7 +7,7 @@ GIT
 PATH
   remote: .
   specs:
-    compass (0.11.beta.5.23f0f03)
+    compass (0.11.beta.5.7ffde70)
       chunky_png (~> 1.1.0)
       sass (>= 3.1.0.alpha.249)
 
diff --git a/lib/compass/configuration/helpers.rb b/lib/compass/configuration/helpers.rb
index 03def3f5..db6f8af6 100644
--- a/lib/compass/configuration/helpers.rb
+++ b/lib/compass/configuration/helpers.rb
@@ -1,5 +1,6 @@
 module Compass
   module Configuration
+    @callbacks_loaded = false
     # The helpers are available as methods on the Compass module. E.g. Compass.configuration
     module Helpers
       def configuration
@@ -65,14 +66,14 @@ module Compass
             Sass::Plugin.add_template_location sass_dir, css_dir
           end
         end
-        unless defined?(CallbacksSetup)
+        unless @callbacks_loaded
           Sass::Plugin.on_updating_stylesheet do |sass_file, css_file|
             Compass.configuration.run_callback(:stylesheet_saved, css_file)
           end
           Sass::Plugin.on_compilation_error do |e, filename, css|
             Compass.configuration.run_callback(:stylesheet_error, filename, e.message)
           end
-          const_set('CallbacksSetup', true)
+          @callbacks_loaded = true
         end
       end