[dider]

OK, It finally works! I still don't know what causes the "invalid capture index" error, but I'm closer.

I uninstalled every modification on my Kindle (except for KAUL and Librerator of course) but the problem persisted.

The only thing that could contain the root of the problem was the "documents" folder itself.

So, first I suspected the collections to cause the problem, as they were created with Calibre's plugin, which used to be very buggy when I was using it back in the day. That didn't change a thing, Librerator still reported "invalid capture index" error.

OK, so I decided to delete all the files from the "documents" folder (except for KUAL of course). It works - no more "invalid capture index" error.

So now I'm wondering which file exactly causes the problem. Is it the name of a file that is problematic or something else? Polish diacritics? Too many files?

I have my buggy "documents" folder copied on my HDD (178MB of files), I'm attaching the list of files from this folder. (Those are mainly books, articles and webpages sent via Calibre and Readability, in English and Polish language). I can upload the files if it helps.