I have just released a new version of the Quickmarks plugin for Eclipse 3.x. This release is purely a bug fix release, correcting two bugs (#1033426 and #1413468) that have been there for almost two years. Finally, they're out of the way... :-)
The new version has been tested on Windows XP with Eclipse 3.0.2 and Eclipse 3.2.
The new version of the plugin can be downloaded here: Quickmarks plugin