This isn't really related to EasyPHP, however...
Firstly, please note I've not installed this product so can't provide a step by step guide, this is just a push in the right direction.
You'll have to determine what build of php you have with your EasyPHP install. Quickest way to do this is to use the code tester from the EasyPHP home page. type in: <?php phpinfo(); ?>
then click on interpret the code.
The first table will tell you your which compiler was used and if thread safety is enabled. Using this information you can download the ionCube install for your install [
www.ioncube.com] For instance my setup uses MSVC9 and thread safety is enabled so I would download the Windows VC9 (x86) version.
I would suggest you choose the Windows Installer version as your question leads me to believe you might not be successful performing a manual install.