I have set the screensaver mode to cover but when I press the power button it comes up with "The ScreenSavers Hack is currently in 'cover' mode, but hasn't yet successfully processed a book cover

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(by the way that smiley in the talking marks is the actual writing not the smiley
I have made sure to make the cover file a proper blank file in my kindle root and have got the latest jailbreak for a compatible version of kindle. (5.3.7.2) I have done all the steps and am not inexperienced with these things and have done lots on my kindle 4 nt. There was a few posts about this earlier on in the thread but the guy with the problem didn't follow up on it. I have also set the time right (not sure where the date is for Kindle touch) and deleted autoreboot and then tried it with autoreboot as well. here is the default kindle metadata and the calibre metadata for a book though they are only screenshots I don't know how to find just the metadata so here is the whole book aswell. I have tried this with quite a few books yet none work.
also seeing as this is my first post thank you to all those main contributors in this forum you have been a massive help.
edit - actually it turns out this doesn't work on kindle 4 nt either. It seems highly likely that the problem is with the books although I've even gone to the effort of downloading new and full metadata off calibre yet it still won't work. so if it is with the books I've tried so many what book metadata actually does work?