Okay, all the loaders can be found here:
http://www.ioncube.com/loaders.php
download and then upload the loader you need for your system, if you are unsure you can download the zip for "all platforms"
Then after uploading point your browser to:
www.yoursite.com/ioncube/ioncube-loader-helper.php
Be sure the loader is located in the ioncube folder, when I did this, by default the loaders are located in a sub folder. To find out which one you need, you can point your browser (after uploading) to:
www.yoursite.com/ioncube/ioncube-loader-helper.php?page=rtl-tester
Then be sure your loader is in the main ioncube folder (an example):
www.yoursite.com/ioncube/ioncube_loader_lin_4.4.so
The helper file is very helpful. It will tell you how to edit the php.ini file, point you to the right loader, where to download it, and etc. If you still need help, you can post here and we will try and resolve any issues you have.