I've installed Aptana on my computer with Windows 7 which has no Internet access. Since I had previously installed Aptana on my iMac, I opened the Applications/Aptana Studio 2.0/plugins folder and I've copied all the .jar files I did need to import on my PC. Typically, they look like these:
Then you have to surf to your plugin folder on your Windows installation and simply paste all the files you've copied there. Once restarted Aptana, all the plugins you've inserted will be automatically loaded by the application.