Tried it anew and it crashed Calibre -- only, this time a found the Fast Loseless Recovery Procedure
: go to ..\calibre\plugins , edit (notepad) Generate Cover.json and change back "colorApplyStroke": true, to "colorApplyStroke": false, save and restart (dunno if the latter is needed, did just for security).
Running XP SP3.
Suspect an ImageMagick issue -- something to do with its font management versus
programs using Windows native font implementation: but my experience with the software is dated by some 4 years or more.
By the way: the plugin is otherwise GREAT -- have used ALL the other features without a snag.