Not sure if this is the best place to provide feedback, but it's the one I could find. Project looks very promising, but does not work with Aptana editors ( http://aptana.com/ ). I was under the impression that Aptana's editors did in fact use the AbstractTextEditor class, so I'm not sure why it doesn't seem to be working (as far as I can tell it works with the PDT editor on the same installation -- I run Aptana as a plugin on Eclipse 3.5 milestone 6).
I personally am not a vim user, but I came across your project and decided to check it out because apparently some people are having problems with the other vi plugins on recent versions of Aptana. If Vrapper can easily be made to work with Aptana's editors, I suspect you would suddenly make a lot of people very happy.