Index: trunk/admin/help/install_help.php
===================================================================
diff -u -r374 -r402
--- trunk/admin/help/install_help.php	(.../install_help.php)	(revision 374)
+++ trunk/admin/help/install_help.php	(.../install_help.php)	(revision 402)
@@ -64,7 +64,7 @@
 }
 $path_char = GetPathChar();
 
-$rootURL = 'http://'.dirname($_SERVER['SERVER_NAME'].$_SERVER['SCRIPT_NAME']);
+$rootURL = 'http://'.dirname($_SERVER['HTTP_HOST'].$_SERVER['SCRIPT_NAME']);
 $rootURL = str_replace('/help','',$rootURL);
 
 $tmp = explode('/', $rootURL);