The first thing to note is that you have to be a member of the SAP Developer's Network (SDN) to get access to the downloads required to do portal development. SAP uses Eclipse but with special class files and plug-ins. The plug-ins allow the creation of par files (portal archives) which can be loaded into EP. So the first steps are to download and install Eclipse and then download and install the Eclipse plug-ins. This version of the plug-ins requires Eclipse 2.1. We are using JDK 1.3 for development.
Next step... develop a simple iView (portlet) using the SAP provided class files.