diff --git a/larpe/trunk/larpe/admin/apache.py b/larpe/trunk/larpe/admin/apache.py
index 060b0f8..3fd607f 100644
--- a/larpe/trunk/larpe/admin/apache.py
+++ b/larpe/trunk/larpe/admin/apache.py
@@ -147,8 +147,8 @@ class Location(object):
     reversed_directory = property(get_reversed_directory)
 
     def get_python_path(self):
-        if hasattr(self.host, 'apache_output_python_filters') and \
-                hasattr(self.host, 'apache_python_paths') and self.host.apache_python_paths:
+        if self.host.apache_output_python_filters and \
+                self.host.apache_python_paths:
             python_path = 'PythonPath "sys.path'
             for path in self.host.apache_python_paths:
                 python_path += "+['%s']" % path
@@ -161,14 +161,14 @@ class Location(object):
     def get_output_filters(self):
         python_filters = ''
         output_filters = []
-        if hasattr(self.host, 'apache_output_python_filters'):
+        if self.host.apache_output_python_filters:
             i = 0
             for filter_file in self.host.apache_output_python_filters:
                 filter_name = 'filter%d' % i
                 python_filters += 'PythonOutputFilter %s %s\n\t\t' % (filter_file, filter_name)
                 output_filters.append(filter_name)
                 i += 1
-        if hasattr(self.host, 'apache_output_filters'):
+        if self.host.apache_output_filters:
             for output_filter in self.host.apache_output_filters:
                 output_filters.append(output_filter)
         if output_filters:
diff --git a/larpe/trunk/larpe/admin/hosts.ptl b/larpe/trunk/larpe/admin/hosts.ptl
index dc11279..72a07ce 100644
--- a/larpe/trunk/larpe/admin/hosts.ptl
+++ b/larpe/trunk/larpe/admin/hosts.ptl
@@ -792,19 +792,21 @@ POST request. You can desactivate some or all of them, or change their value.'''
         self.host.store()
 
     def generate_apache_filters(self):
-        # Set Python filter path for Apache configuration
+        self.host.apache_python_paths = []
+        self.host.apache_output_python_filters = []
         site_auth = site_authentication.get_site_authentication(self.host)
         filters = site_auth.get_filters()
         replace_login_form = self.host.auth_form_places == 'form_everywhere' and \
                 self.host.auth_form_action
-        python_path = os.path.join(self.host.site_dir, 'filters')
-        if python_path not in self.host.apache_python_paths:
-            self.host.apache_python_paths.append(python_path)
-
-        # Write Python filter
-        python_file = open(os.path.join(self.host.site_dir, 'filters', 'output_replace_form.py'), 'w')
-        python_file.write(open(OUTPUT_FILTER_BASE).read())
         if filters or replace_login_form:
+            # Set Python filter path for Apache configuration
+            python_path = os.path.join(self.host.site_dir, 'filters')
+            if python_path not in self.host.apache_python_paths:
+                self.host.apache_python_paths.append(python_path)
+
+            # Write Python filter
+            python_file = open(os.path.join(self.host.site_dir, 'filters', 'output_replace_form.py'), 'w')
+            python_file.write(open(OUTPUT_FILTER_BASE).read())
             python_file.write("def filter_page(filter, page):\n")
             if replace_login_form:
                 python_file.write('''\
@@ -819,10 +821,6 @@ POST request. You can desactivate some or all of them, or change their value.'''
             # Set Python filter for Apache configuration
             if not 'output_replace_form' in self.host.apache_output_python_filters:
                 self.host.apache_output_python_filters.append('output_replace_form')
-        else:
-            if 'output_replace_form' in self.host.apache_output_python_filters:
-                self.host.apache_output_python_filters.remove('output_replace_form')
-
 
     def sso_init_link [html] (self):
         form = self.form_sso_init_link()
diff --git a/larpe/trunk/larpe/site_authentication.ptl b/larpe/trunk/larpe/site_authentication.ptl
index b90d942..638a53a 100644
--- a/larpe/trunk/larpe/site_authentication.ptl
+++ b/larpe/trunk/larpe/site_authentication.ptl
@@ -115,7 +115,7 @@ class SiteAuthentication:
             filters.append(filter)
             return filters
         """
-        return None
+        return list()
 
     def submit_local_auth_form(self, form):
         username = form.get_widget('username').parse()