Thanks for replying. I tred updating the JSON manually to change allFields from a simple string to an array, which solved the initial problem, but then I got other errors with the scf-messages page in particular... I seem to have got my system into a proper mess so will probably need to reinstall from scratch.
One thing that puzzles me is that the documentation has changed a lot since version 0.2.1 - I can't see any reference to the scf-messages page at all in version 1.07 for example.