@marrco: Nope, this is the same error as @arooni, which I have failed to replicate and/or fix, apparently

.
c.f.,
#287.
(I still need that full debug log to help figure out what might be going wrong, you can PM it to me if you want to avoid showing the contents of your Kindle library to the world).
EDIT: Random question is random: are you running macOS, too?