Originally Posted by i♥cabbages
Hmm. You are running unswindle with K4PC *closed*, yes? The unswindle script then launches K4PC for you. You do the need to open the book in question (not just highlight it). If that doesn't immediately help, could you try running it a few times, just to make sure it isn't some intermittent condition I'm not handling properly?
I tried with a bunch of books and got the same error; with K4PC closed, unswindle opens it and shows the books; when I try to open a book by double clicking, the error comes.
I open KP4C directly, open a book and close K4PC and then run unswindle, it gives the error immediately without opening KP4C