PHP5.3之后不再使用Zend Optimizer而是由Zend Guard Loader替换，而Zend Guard Loader安装比前者方便了很多，只有一个dll：

址：http://downloads.zend.com/guard/5.1.0EA/ZendGuardLoader-php-5.3-Windows.zip

下载好后解压压缩包，找到 ZendGuardLoader-php-5.3-Windows\ZendServer\lib\loader\php-5.3.x 目录下的 ZendLoader.dll 文件，将它放到你的php目录下ext下，再编辑php.ini文件，添加一段代码（如）：
[Zend.loader]
zend_loader.enable=1
zend_loader.disable_licensing=1
zend_loader.obfuscation_level_support=3
zend_loader.license_path=
zend_extension=”d:\php\ext\ZendLoader.dll”

session already sent 错误的解决方法：
You've an extra blank line on a php file that you've edited recently, possibly includes/joomla.php, but not necessarily.
If you've edited a php file, config or a remos file perhaps laterly, load it into an editor and see if there is a blank line either before the <?PHP or after the final ?> at the bottom of the page.
Some website editors do like to add an extra blank line each time you edit a php file in them!