diff --git a/app/controllers/file_controller.rb b/app/controllers/file_controller.rb
index 03817c2a..2e293641 100644
--- a/app/controllers/file_controller.rb
+++ b/app/controllers/file_controller.rb
@@ -26,7 +26,7 @@ class FileController < ApplicationController
       end
     else
       # no form supplied, this is a request to download the file
-      file = @web.files_path + '/' + @file_name
+      file = @web.files_path.join(@file_name)
       if File.exists?(file)
         send_file(file)
       else
@@ -38,7 +38,7 @@ class FileController < ApplicationController
   end
   
   def blahtex_png
-    send_file(@web.blahtex_pngs_path + '/' + params['id'])
+    send_file(@web.blahtex_pngs_path.join(params['id']))
   end
     
   def delete
diff --git a/app/models/web.rb b/app/models/web.rb
index b2e7e6c2..c9571738 100644
--- a/app/models/web.rb
+++ b/app/models/web.rb
@@ -128,21 +128,18 @@ class Web < ActiveRecord::Base
             "#{File.expand_path(dir)} and add files to it."
     end
   end
-  
+
   def files_path
+    path = Rails.root.join("webs")
     if default_web?
-      "#{RAILS_ROOT}/webs/files"
+      path.join("files")
     else
-      "#{RAILS_ROOT}/webs/#{self.address}/files"
+      path.join(address, "files")
     end
   end
 
   def blahtex_pngs_path
-    if default_web?
-      "#{RAILS_ROOT}/webs/files/pngs"
-    else
-      "#{RAILS_ROOT}/webs/#{self.address}/files/pngs"
-    end
+    files_path.join("pngs")
   end
 
   private
diff --git a/app/models/wiki_file.rb b/app/models/wiki_file.rb
index ba122662..5e9a5d21 100644
--- a/app/models/wiki_file.rb
+++ b/app/models/wiki_file.rb
@@ -46,7 +46,7 @@ class WikiFile < ActiveRecord::Base
   end
   
   def content_path
-    web.files_path + '/' + file_name
+    web.files_path.join(file_name)
   end
   
   def write_content_to_file
diff --git a/test/unit/page_renderer_test.rb b/test/unit/page_renderer_test.rb
index 3e170fcb..71277f91 100644
--- a/test/unit/page_renderer_test.rb
+++ b/test/unit/page_renderer_test.rb
@@ -211,6 +211,13 @@ END_THM
   end
   
   def test_have_latest_itex2mml  
+    assert_markup_parsed_as(
+        %{<p>equation <math class='maruku-mathml' displa} +
+        %{y='inline' xmlns='http://www.w3.org/1998/Math/} +
+        %{MathML'><munder><mi>A</mi><mo>\314\262</mo></m} +
+        %{under></math></p>},
+        "equation $\\underline{A}$")
+
     assert_markup_parsed_as(
         %{<p>equation <math class='maruku-mathml' } +
         %{display='inline' xmlns='http://www.w3.org/1998/Math/MathML'>} +
@@ -220,13 +227,13 @@ END_THM
     assert_markup_parsed_as(
         %{<p>blackboard digits: <math class='maruku-mathml' display='} +
         %{inline' xmlns='http://www.w3.org/1998/Math/MathML'><mi>math} +
-        %{bb</mi><mn>123 </mn></math></p>},
+        %{bb</mi><mn>123</mn></math></p>},
         "blackboard digits: $\mathbb{123}$")
 
     assert_markup_parsed_as(
         %{<p>\\rlap: <math class='maruku-mathml' display='} +
         %{inline' xmlns='http://www.w3.org/1998/Math/MathML'><mpadded} +
-        %{ width='0'><mn>123 </mn></mpadded></math></p>},
+        %{ width='0'><mn>123</mn></mpadded></math></p>},
         '\rlap: $\rlap{123}$')
   end