Released v2.3 \o/.
I also updated the Helper extension to be slightly smarter (ie. mostly model-aware), and stepk's KUAL add-ons one to work in tandem with the latest version on the sorting buttons front ;p.
See the NEWS file for more details, but basically:
* PW2 support
* Cleans itself up on exit
* Minor under-the-hood changes (cleanup/refactoring/fixes/performance)
Also:
the filename changed! Pay attention to that

. Delete the previous version (preferably from the Kindle's UI, if you don't want a broken thumbnail on FW 5.x) before copying the new one

.
The first post should have been updated to reflect these changes, but if something doesn't make sense, do mention it

.