diff -Naur WebCalendar-1.2.0.orig/includes/classes/WebCalendar.class WebCalendar-1.2.0.new/includes/classes/WebCalendar.class
--- WebCalendar-1.2.0.orig/includes/classes/WebCalendar.class	2009-06-08 15:11:46.000000000 +0200
+++ WebCalendar-1.2.0.new/includes/classes/WebCalendar.class	2009-06-08 15:23:15.000000000 +0200
@@ -729,9 +729,15 @@
           $user_email = $login_email;
         } else {
           // Invalid login.
-          if ( $use_http_auth )
-            send_http_login ();
-          else
+          if ( $use_http_auth ) {
+            if ($pub_acc_enabled) {
+              $login = '__public__';
+              $firstname = $lastname = $user_email = '';
+              $fullname = 'Public Access';
+              $is_admin = false;
+            } else
+              send_http_login ();
+          } else
             // This shouldn't happen since login should be validated in validate.php.
             // If it does happen, it means we received an invalid login cookie.
             do_redirect ( $login_url . '&error=Invalid+session+found.' );