Install Flash Builder 4.5 for PHP - For more information see the Flash Builder 4.5 for PHP Installation Guide.
Zend Server 5.x or above, or a compatible PHP web application server.
You will need a PHP application server to debug your application. Go to http://www.zend.com/en/downloads/ to downlaod Zend Server 5.x, the Zend PHP application server. For more information see the Zend Server Installation Guide.
The Zend Server Installer includes optional components that can be downloaded as a part of the installation process.
Zend Studio is the professional PHP IDE designed to “mobilize” PHP apps and boost developers’ productivity. It helps create and maintain PHP code effectively, solve problems quickly, deploy in the cloud and improve team collaboration.
Source: http://files.zend.com/help/Flash-Builde ... cation.htm
I hope this helps. Thank you.