WoSch - move 'your' library inside the Calibre Portable folder. maybe rename it first to something like MyLibrary, so your Calibre Portable folder would have:
Code:
folder Calibre
folder Calibre Library
folder Calibre Settings
folder MyLibrary
file calibre-portable.exe
Now use the Library/Switch Create feature to 'hook' the MyLibrary folder as an existing library.
BR