Hi Tim,
nothing works... I also tried Worfence Assistant but wasn't able to use that either - same error message when I tried to select "Delete all Wordfence data in your database".
I deleted all data in the database manually, installed it fresh - but the problem still exists.
I guess I have to look for alternatives here and replace yuor plugin which would be sad, I really like Wordfence, it works fine on all my clients website except on my own... http://jobshubnct.org.au/.
Cheers
Thomas