I downloaded and unzipped lilypondtool-2.14.20111117.zip over the top of the previous version of Lilypondtool in my .jedit folder. The one thing that doesn't work for me with this preview version is to run convert-ly from the toolbar or menu. When I do that, nothing happens (no console window appears) and the version number in the ly file doesn't update. The plugin options (path to lilypond binaries, convert-ly command, etc) are correctly set and the same as they were in the previous version, where this worked. convert-ly runs from the command line without any problem.
Jedit is v4.4.1 on Ubuntu 10.04 with current Sun Java.