It's too late tonight so I'll have to look at print statements tomorrow.
However, just in case I didn't explain myself well enough, my calibre installation has no problem installing, assigning to toolbar, running the plugin. It's just that after restarting calibre the master 'Plugin Updater' tool lists "Scramble Ebook" in its "not installed" filtered list and doesn't list "ScrambleEbook" at all.
I've checked my plugin code and I don't see any occurrences of "Scramble Ebook" (with space) at all, only "ScrambleEbook".
In addition, in case any are relevant:
- the plugin zipfile in the config directory after installation is called ScrambleEbook.zip (no space).
- It shows as "ScrambleEbook (0.0.4)" in the list Prefs - Plugins - User Interface Action plugins
- I did notice that the MR "Index of Plugins" thread shows it as "Scramble Ebook" (with space)