I have the 64-bit version of Eclipse running with the WB plugin under windows.
Probably, I am missing something.
When I purchased the Workbench 2.xx license, I just ran the installer then launched Mathematica and everything worked (not as I expected but it worked). In other words, to run Workbench I did not need anything extra (as for example and additional piece of software not included in Workbench, say, Eclipse). What I am saying is that I understood that Eclipse was, somehow, included in Workbench 2.xx.
To me, this is a bit confusing.
Which is the difference now between Workbench 2.xx and the new Workbench (3.xx) ?
The difference is that Workbench 2 doesn’t work with new versions of Mathematica (e.g. M11). You need WB3 for M11.
WB3 is a plugin to Eclipse. You need to install Eclipse first. Detailed instructions are here:
Personally I have always preferred the plugin version to installing multiple versions of Eclipse (one “Eclipse” and one “Workbench”).
Many thanks.
Related: Workbench now compatible with Wolfram Language and Mathematica 10 and 11