Sounds like you have really tried to get it going, hopefully I can give you a few pointers to help you get up and working with this great plugin for Eclipse.
Before you start, you must have the correct version of the Arduino IDE already installed on your Mac. You can check on Jantje's site for the correct version you need for a specific version of the plugin. I do find it confusing how Jantje has detailed this and would like to see his instructions for this laid out differently so it is more clear and understandable. But, basically, only certain versions of the Arduino IDE can be used with the plugin. I believe this is because of changes in the way Arduino do things.
But, to let you know I use and others suggest using Arduino version 1.5.2 beta.
I use this version as I am playing with the DUE as well.
There are two basic approaches to having Eclipse work with Arduino, so that you can program and upload from Eclipse to your connected Arduino.
The first is along the lines of what you have done, and this was Jantje's first method of installation.
For this, you needed to download and install, as you have done the specified version of Eclipse CDT (The C/C++ dev system). After checking that Eclipse was installed and working correctly, you would then proceed to install Jantje's plugin.
Normally this is done from within Eclipse.
You can see this here http://www.baeyens.it/eclipse/Install_plugin.shtml
From there you will see that you need to run up Eclipse and the select 'Help | Install New Software.
Follow the instructions step by step and you should end up with a system that works.
Also, as you are also on a Mac, this may also interest you, a link from Jantje's site http://trippylighting.com/teensy-arduino-ect/arduino-eclipse-plugin/arduino-eclipse-ide-and-plugin-v2-2-installation/
Right, the second method, is far easier and should have you up and working in a very short time.
That is download one of Jan's prebuilt packages from his download area, http://www.baeyens.it/eclipse/download.php
Go down to see the Mac OSX packages and select a recent version.
You will need to unzip it and then you can install it..
Now, the problem.
I tried a few of these packages last week for you already, but, as you know I had problems with the installation.
I emailed Jan about this, but he is unfortunately unable to test the situation as he doesn't have a Mac.
To further test my research, I downloaded a bete testers package for Mac OSX and that installed fine for me.
Maybe you might like to try to download a prebuilt package from the download area with the link above and try.
That way, if you have problems, you may tell Jan and we will then need to see what the problem there is.
Maybe it was just me and I did something incorrect, but I tried on both my Macbook Pro and Mac Mini with the same results.
Both installs from the download are failed to install correctly,with errors being generated during the unzip process.
Yet on both my Mac's I could use the beta testers prebuilt package just fine.
Ok, I think that should be enough to get you well and truly confused Ersan